I'm not sure how people take issues with what Kawazu said.
He is being asked about Switch's effect in general to video game industry, not whether he will make his game available for Switch (which he already did).
I feel his answers is quite logical. Switch will get more games if developers feel it brought over 3DS audience.
3DS game have narrower scope and lower budget in general, so of course lower production value can give publishers/developers more leeway to take risks and develop more titles. Switch will absolutely get more games if developers aim for 3DS scale of games.
If you know Kawazu, his game does not ever try for cutting edge graphic or utilize hardware gimmick.
His game system tends to be the innovation in itself.
If he makes another game, I'm quite sure he will try to port to as many platform as possible, provided SE give their support.
Problem is his type of game is extremely niche, so I don't even expect new entries for at least 3-4 years or so if any.
I'm actually very surprised SE greenlighted Scarlet Grace.
All in all, Kawazu is rather irrelevant if you are talking about third party support.