IIRC Game Freak also started developing Sword and Shield immediately after Sun and Moon's release, which makes it even more plausible that they expected it to be a 3DS title rather than a Switch one.

If this truly is the case, that actually makes the situation a lot worse, as it means they had some horrible forethought and faced the consequences of combining it with a multibillion-dollar franchise that requires multiple stuff to come out in a specific timeframe. Meaning that this is a greater fuck-up than anyone could've imagined. At the very least it explains a lot of its faults, but at the same time it shows that Game Freak has seriously lost their grip on how to maintain the gaming facet of the Pokemon franchise.

Ideally, for Gen IX they should be able to learn from these mistakes to prevent a similar catastrophe, but I wouldn't expect it to change the quality of the games themselves given that this is Game Freak we're talking about.

As always this is just speculation.

This might explain all the negative we have seeing so far from the games. But we may not know until the games come out and dataminers find the code used in the games.