In Japan, new Pocket Monster games means new logos. In the West, it does not. And that sucks!
As pointed out by a KnowYourMeme user, here's how the the logos for the Japanese versions and the Western versions of all the Pokémon games compare through the years.
That's right, the Japanese logos continue to evolve and flourish. The Western ones do not. (Perhaps, that is to keep the branding consistent for Western players?)
Chin up, it's not totally depressing. Western Pocket Monster fans will point out, the subtitles of each game do change. For example, check out the subtitles for Crystal, the ones for HeartGold, and the ones for Black. A lot of evolution there!
Evolution of Pokemon Logos [KnowYourMeme]