But of course, Shoot 'em ups are one of the genres left untainted by the demand for easier and easier games, the very notion of changing that comes close to setting a hornet's nest on fire.
Way to go completely ignoring the arguments presented in the thread and just going "well they're just elitist". You're sounding really passive-aggressively snarky for someone who seemingly just glazed over the meaty posts. EDIT: lol my mistake whoops. I posted a wall anyways.
The series is a danmaku (translator's note: it means bullet curtain, because there are supposed to be a lot of bullets) that is renowned for its difficulty and beauty. As people play the games, they don't get progressively worse through practice, and they aren't trying to not-clear the games. You don't have to open up a new, easier difficulty because people spontaneously have the desire to fail at the games and therefore need easier difficulties to fail at. When you talk about game series becoming progressively easier, you're actually talking about lowering the barrier to entry. You're talking about opening the genre up to people who have no initial desire to improve and complete the game, but rather to get the instant gratification of completing the game without much effort at all. You're talking about people who are being introduced to video games or don't have an attention span great enough to stay on a single difficult task without giving up and doing something else. If the series did need to become easier, it would be because the lowest difficulty is too difficult for people to obtain interest in the game, to the extent that you are actually losing a significant amount of sales. And if you were talking about a game that is attempting to target a certain casual audience and the producers had to make a decision on whether to lower the barrier to entry so today's little kids can play Mario for two minutes without throwing the controller out the window, then you'd be right; that, unfortunately, is a good idea.
However, Touhou is a doujin project that is run by a single person, and doesn't rely exclusively on sales, so the number of people playing the games does not really affect the game's structure. Furthermore, Touhou's notoriety is already greatly established. If people want to play the games, it's because they want to delve into the challenging realm that is danmaku. They've almost certainly seen someone else playing, whether a video or in person. If they want to play and actively get good enough to clear some difficulty, then they know they're in for a bumpy ride. If they go even further, then that applies even more so. If they don't want to actually play the games, but instead create doujin material like music and books and art because they're interested in that side of Touhou, then awesome for them; that's probably a significant portion of the fandom. They don't have any bearing on the overall demographic of the people who play the games.
Now, if we're talking about the people who want to clear the game, but are currently so bad that they need a lowest difficulty, they have... IN Easy. Arguably the easiest entry in all of Touhou. If you made something much easier than IN Easy, I'd be inclined to reject it as actually being a danmaku anymore. It'd be more like playing a VN where the only bad options are things like "burn your house down" and "see if you can fit that whole knife in your throat". From IN Easy, the difficulties throughout all the games mesh into a fabric that basically has something for everyone between there, and UFO Lunatic. I don't think there is anyone who fits into that range who is left out. Anyone who's made it to the point of UFO Lunatic has a game that probably yields a sufficient challenge such that they struggle to beat it but can feasibly aim for completion. Through demographics alone, it's pretty safe to say that if anything, the Easy and Normal mode players have a greater variety of games and difficulties to challenge them, than the Lunatic players do. The gaps in difficulty increase fairly non-linearly, so naturally the Lunatic players have less to work with (this is also why many venture towards other danmaku series). And that's okay; the demographics also point out that the vast majority of Touhou players fit into the Easy-Normal categories. Moreso, the Hard and Lunatic players have likely been playing so long that the challenge alone is enough motivation. The ever-slightly larger gap in difficulty is equalized by the player's insistence that beating it is a feasible goal, and that mindset is learned through practice and clearing the easier difficulties.
As said, people do not attempt to get worse at a game and therefore need easier difficulties. After time, people improve at the game. They get better and better until they can conquer everything there currently is to offer. Until there is nothing left to challenge and you need to make up your own challenges or go find another game series. The Lunatic players do not need to play an Easy mode. They do not need to play a Normal, or a Hard mode. They want their own difficulty, they want a Lunatic mode. They want a Lunatic mode that gives them a challenge. They don't necessarily want one that trumps the previous record-holder of ass-rape, but they want something that will keep them interested and, you know, actually challenge them. 10D was not this. 10D has one of the easiest Lunatic modes in the series, akin to PCB and MoF (with bombs). I don't think anyone expected another UFO, but 10D is truly not very exciting for us. The mechanics don't even have a big hand in this; the raw danmaku is easy, as a Lunatic mode: wait no, as "the hardest difficulty in the game". Bar overdrive, but that isn't a game. People often say that ZUN makes the games largely for himself, so you shouldn't question changes made. To an extent I find this true, but if this were invariably the case, by that reasoning he would have also made consecutive games harder because he got better. He would not make himself difficulties that challenge him further and further, then suddenly drop, unless he had a stroke or something.
If the Lunatics get something they're happy with, then you look at what your bottommost difficulty range is. From those two points, you balance the middle. Obviously, I don't mean disregard the opinions of the players who play at lower difficulty, but mainly you should look at the people who are left looking for something to challenge. It may seem a bit selfish to say that ensuring the difficulty of Lunatic is a priority, but that's really how it naturally turns out. When you balance everything properly, you have your lowermost range which should stay relatively steady throughout the series, you should have your uppermost range which tickles the fancy of the top players, and the in-between difficulties take care of themselves. The jumps in difficulty between each rank shouldn't vary much even if you increase the highest difficulty a lot: the jumps should clearly increase about a third as much as the highest increase, and that's even considering there's a max increase at all. If everything stayed the same difficulty as UFO there shouldn't be any change in climb. However, since not every player can look up to UFO Lunatic and still want something to do, the difficulty of Lunatic as the series progresses should dip a little before climbing and reaching a new peak. 10D was clearly too much, but if it dipped to say MoF Lunatic without the whole bomb abuse, then rose to SA and UFO again, that would be a good scenario for all parties. Even if it did eventually progress to a point where the jump between difficulties becomes too much for most people, they still have the other games to play, which people naturally become interested in, and as said before, they make a pretty even fabric of difficulties.
Now I'm pretty sure the claims we're making in this thread have been made perfectly clear. Ahem. I've had a bit too much wine. I think I'm done.