I dunno for sure, is just my observation. I understand nintendo doing it but as for 3rd parties is just seem to me like they aren't fully on board until they start making a brand new game rather than 2012 ports of old ones. This and the rumors of "Buy this game or we don't make new ones" seem very offensive. I mean if they really wanted to test waters with ports then what was nintendo upfront about the support from developers? It makes them look a bit suspicious. Of course is just my opinion.I kind of agree with @Sonic Angel Knight . It's pretty clear that third parties don't have faith in the Switch just yet, and you can't really blame them. They're generally not making anything new for it. I'm pretty happy about Atlus making SMT V for the Switch.
To me, most of the games could have existed on the wii u but just didn't bother. Had it did, maybe perhaps help sales of the system. I know that isn't only to blame, nintendo marketing of the console wasn't very good, no one wasn't even sure what the wii u was when they announced it, and all we saw was a tablet, they could have tried a bit better. It had potential, especially if they made accessory to play 3DS games on wii u in upscaled resolution, would have been a good idea also better for recording it for youtube videos. They just focused too much on 3DS cause it was more popular, and thought they didn't need those extra 3rd party games to buffer their release dates of the first party titles.