Until you realize Let's Go and SwSh were practically running in parallel at some point. You compare SwSh and LGPE to HGSS and DP, but HGSS was released thrice the time after DP than SwSh after LGPE.I hate to be that guy, but the problem with SwSh is that Game Freak already trial ran the new console’s hardware with Let’s Go!. In that sense, SwSh were the second games on the new console, the HGSS to DP, and the step up in programming quality was much less than in that instance.
We know that Sword and Shield started development after Sun and Moon were finished. They've said as such in the interview.
Which means that, at some period of time between 2016 and 2019, Game Freak was working on FOUR games at the same time:
- Sword and Shield
- Let's Go Pikachu and Eevee
- Ultra Sun and Moon (which we know it was handled by the younger Game Freak personnel, as it was mentioned in an interview as well)
- Little Town (that non-Pokémon game they were working on)
Game Freak might have a history of not handling console debut games very well, but the real problem was awful planning. The debut traditional Pokémon game on the Switch might as well have had only a quarter of the potential workforce dedicated to it at some point. Too many cooks spoil the soup, they say.