Gensokyo is supposed to be a medieval Japanese society, yet there are so many anachronisms even in scenes where the Kappa, Tengu and Moriya Shrine are not involved.
Let's start with what we know:
[Don't remember source] Akyuu is stated to like FM Synth Music. But...where is she getting FM Synth Music? How does she even know the stuff exist?
[Three Fairies] Reimu and Marisa stumbles upon a radio tower. Anachronism is averted as they have no idea what it is. But then played straight when Marisa imagines climbing to the top of it and shouting through a (clearly modern and electronic) megaphone upon being told it is a means to communicate; and Reimu, believing it to be a weapon, imagines something along the lines of an
Inter-continental Ballistic Missile. How the heck did they know about electronic megaphones and ICBMs???
[Three Fairies] The Three Fairies gets inside Alice's house. One page consist entirely of a single page-sized panel of Alice controlling the dolls to make tea. Now, Alice being European, all the medieval/renaissance(?)-era European silverwares and stuff are acceptable...but not a very obviously modern carton of milk (that
even has a barcode on it) being handled by one of the dolls. Where did Alice get that modern milk carton? No way it came from the Outside World...
[WaHH] Reimu has had major events at the Hakurei Shrine. She advertises all of them...using flyers that have blatantly modern designs. One chapter at least justifies it by having Nitori and her Kappa mob backing the event. But not the ones without the Kappa. Where is she getting those modern-style flyers?
[PoDD] Reimu references
Doraemon (then-most famous pop culture of Asia), knows what an
android is, ponders if Ruukoto ran on batteries (not knowing that Ruukoto is nuclear). Kotohime recognizes all the quantum-physics-powered tech on Yumemi's Probability Hyperspace Vessel, and recites the Periodic Table as one of her victory quotes. Where do those knowledge come from???
[LLS]
So its safe to say that ZUN (and by extension Hirasaka Makoto and Azuma Aya too) is extremely inconsistent about Gensokyo's technological cultures.
Your opinions on the matter?