...Hold on, why do the police sometimes call Kimiko Pikachu? Wasn't Pokémon Red/Green a 1996 release?
Law of Conservation of Good Fiction. With at least three major late '80s and early '90s Japanese IPs disappearing from fiction because they're, uh,
fact... Pokemon got timewarped forwards into the
early '90s, as one of the first wave of GameBoy games.
Zakenna, During PreCure crossover: "ZAKENNA!"
Sailor Moon: "Wait... are you a Pokemon named Zakenna? Are Pokemon real now? Because I... I don't think I could handle fighting an evil Jigglypuff."
Naru: "I seriously considered devouring a demon to amplify the corrupted dark powers that I strongly suspect I have now, and even
I agree that no middle school girl should have to face such a terrible necessity."
Funny thing is, all the villains would need to do to, if not actually win, at least progress a LOT in their plans, would be to attack ANYWHERE THAT IS NOT TOKYO.
Sure, we have the silver crystal, but if the DK had youma in literally every country of the world they could get a LOT of life energy BEFORE coming at us for that!
I suspect the underlying problems with that idea are as follows:
1) We've observed that
isolated youma plots, the kind where you plunk down one youma and have them gather energy, are not
THAT hard for some random magically empowered individual to trip over and destroy. Even mortal authorities have a chance of neutralizing the plot eventually- by warning away other mortals, if nothing else.
2) Because of (1), for youma plots to work reasonably well in the face of even the kind of scattershot opposition modern Earth is capable of
without magical girls blowing everything up the way they do in Tokyo, they need a competent field agent handling things. Someone to make sure the plot won't be outed immediately, and to handle any low-tier opposition the youma themselves isn't strong or smart enough to squash out of hand.
3) To deal with (2), the Dark Kingdom has about
four field agents capable of overseeing an important operation. Those four may or may not be able to casually teleport over intercontinental distances without considerable prep time or energy expenditure. Sure,
we can do it, but we have enormous reserves of planetary magic on tap and even for us there's a cooldown period. The Dark Generals, who are specifically trying to conserve energy so they can feed it to Metallia, and who don't have the planetary magic wells to draw on directly, may have more trouble.
4) Time zones are an issue for them as well as for us. Youma may or may not need to do things like sleep, but their harvesting activities are necessarily going to be tied into the time rhythm of the communities around them. If a Shitennou tries to supervise operations in, say, China, Germany, and Brazil all at the same time, he's going to spend a lot of time grumbling about jet lag.
5) Furthermore, local knowledge is an issue. The Dark Generals don't necessarily have unlimited translation magic or magical knowledge of all Earthly languages; it's very unlikely that their youma do. For youma to pass as human they have to know how humans behave in the target area; to set up front operations like shops and gyms they have to know how to navigate the local bureaucracy and economy. Figuring this out in each new area represents a further obstacle that must be overcome.
Between (3), (4), and (5), spreading out their operations on any scale much larger than a major metropolitan area or small country might well cause the Dark Kingdom more logistical problems than it solves.
Furthermore, there was simply
no need to do anything like this for them until about a month ago, when abruptly Sailor Senshi (and other, entirely unrelated groups of magical girls) started awakening in droves around Tokyo. Which presents the Dark Kingdom with a bit of a dilemma. If they bail out of the Tokyo area and start up somewhere else, they're giving their new enemies (whose command structure they don't fully understand) room to fortify, train, and become a threat capable of coming after them. If they stay
in the Tokyo area, they need every tool at their disposal to keep the situation from spiraling hopelessly out of control.
Jadeite definitely seems to be trying the latter- though it may get him killed.