Pokemon games have generally been under performing at retail over the years. And this is before we have GameFreak legitimately making a new generation worse than previous entries.
https://vgsales.fandom.com/wiki/Pok%C3%A9mon#cite_note-sales-5Before, Pokemon started under performing because of how fast the franchise blew up. With the first gen, that was 90% of the content that was available for Pokemon. The anime got the games green lit for sales outside Japan, and the hype was at it's highest. By gen 2, you had a fully realized anime, movie, toys, music albums, trading card game, and more that I might be forgetting. If a games wasn't really what someone wanted, there was other merchandise and content for them. The Pokemon Trademark is the biggest competition the games face, and other games make
Now look at Sword and Shield coming up, on the coat tails of Detective Pikachu, an anime reboot, a stronger than ever card game, and the pragmatic 'success' that was Let's Go. It's going to be missing over 60% of the Pokedex and play like a horribly optimized up-scaled 3DS game. And GameFreak lied about it for the whole ride here.
The Dumpster fire will be hot and heavy.