BW's sales were fine. They were released when the 3DS was right around the corner. Masuda did learn that a "fresh start" (really just in terms of the Pokedex) wasn't what most fans wanted, which is fine.
It's Game Freak and TPCi who prioritize Kanto (for logical reasons), not the anime. SV don't do anything special with Kanto Pokemon (Johto got more evolutions and Paradox species), so this isn't the best time to complain. As for the anime, let's break it down:
OS: One cohesive story. More could have been done with the Johto team.
AG: FRLG promotion and the 10th anniversary. The biggest OS tribute was a special that didn't even get a TV broadcast in Japan. Kanto felt like a different region.
DP: Very little Kanto aside from two Gary episodes.
BW: They used Charizard (after Dawn and Cynthia) to boost the ratings. Nothing of note happened with it, and Mewtwo was replaced just because.
XY: They gave Mega Charizard X to a new character instead of Ash, who focused on Greninja. No real callbacks to any series.
SM: They gave Misty and Brock two returns (for the 20th anniversary and LGPE promotion) after writing them out of a movie, which could have been canon otherwise. Misty had been missing for 11 years at that point.
PM2019: For a series with many episodes set in Vermilion, we didn't even see Lt. Surge or Squirtle. Kanto Pokemon were prioritized for fillers, but not the actual region or characters. Even Gary was brought back for Go, not Ash.
MPM: Badly needed to make Ash's story come full circle. No, we don't need to see all the characters that already came back in PM2019 and got closure. The reserves are enough to remind us of the other series.