After all of the controversy with the lack of content and corners cut, I expected SOME kind of negative reaction. Slightly lower sales, shorter legs, something. Instead not only it becomes a massively successful launch, it becomes the immediately crosses the 15 million mark that most Pokemon games need all of its lifetime to reach and it's going to end up becoming the second best seller in the franchise. This is sad because either the hardcore fans who said to boycott this bought it anyway, thus giving up on future games becoming better, or the casual base is so big it can more than compensate for the loss of the core base, thus making any kind of customer reaction powerless. Either way, GameFreak and The Pokemon Co. is just going to continue to degrade the series to sell more games faster and faster.
Like I said, I very much doubt many hardcore fans boycotted it. I bet 99% of them bought it but then just complained endlessly online (and the other 1% will eventually buy it). If you are a hardcore Pokemon fan are you really not going to buy the first core Pokemon game for a console? Unlikely.
Also there are plenty of people who don't buy Nintendo portables but have a Switch, so don't normally buy Pokemon games because they don't own those systems, who got this game (me for instance - this is my first pokemon game since I got Red in 1999). So yeah the expanded sales opportunities the Switch fan base affords can easily make up for any tiny percentage of hardcore fans who did actually boycott the game.
Also like I said I think we see the negative reaction in that it didn't sell even more than it has! We see Animal Crossing, a much smaller franchise, beating Pokemon's initial launch. And while in the 6 week post-launch numbers Pokemon did over 2.6 million more, again that was the holidays for Pokemon and Pokemon is known as a more launch heavy seller, and it did indeed drop off drastically after the holidays while Animal Crossing seems likely to sell far more than Pokemon during their respective second quarter of sales. That should make us realize just how much bigger Pokemon Sword/Shield could have been if it had gotten the good word of mouth that games like Botw, Odyssey, Smash, AC have all had. If Pokemon had been a critically acclaimed game it would probably be a couple million higher right now. While I think Pokemon not being critically acclaimed the way many Switch games have been is hurting it more than any hardcore-fan-only controversy, I'm sure the negative news of the controversy did play a bit into the wider so-so acclaim for the general market reaction to the game.