Yeah no. Anyone who's remotely into video games has heard of Metroid. Touhou on the other hand, you could probably go through hundreds of people before you found someone who's heard of it.
Times are changing. Those people who are remotely into video games are just people who are average gamers. Yet still even a small portion of these gamers doesn't know Metroid.
For one reason, not a large percentage of gamers even likes Nintendo(which are the hard hard hardcore Sony and Microsoft Fanboys, and which are also mostly kids-young adults).
If the average person doesn't lurk as much as "we" do, they don't post and know much about Nintendo on the internet these days. And for a seemingly dying game like Metroid, of course they wouldn't know. Touhou per se due to the large amount of fan-based material over the internet, it's enough to get anyone's attention(eg. facebook spams, 4chan, youtube, your friends, cameos, other, and the so-called Death Waltz incident was enough for average person to look it over what it was actually).
To summarize, Metroid is old, and hasn't had enough spotlight these days. One of the reasons why it's on the top list would be it's loyal fans, and probably people(mostly older ones) who knows it.
But that doesn't mean Metroid's the only one, there are still a lot, like Donkey Kong, Earthbound, Doom, Quake(Especially true, when FPS talks these days consists of what? COD and BF most of the times), and a lot more. Unless they're put on the spotlight again, they won't shine as much as others.
Still that's from my perspective.