Vita did not sell well in japan. 5 million units in 5 years, when it's predecessor did around 4 times that? I mean it's pretty clear that the bar is being lowered here and that the japanese market is dying. Is there even a real debate here? We are talking about factual numbers and PS3 sold less than half it's Predecessor as well.
Hell, just under a week ago, NIS even announced a new game for Vita/PS4 (and again, no Switch version whatsoever).
Vita is a failure even in japan. It didnt sell anywhere near PSP. Saying that PS4 sold just as well as Vita is not reassuring. It just recently outsold WiiU LTD despite WiiU being pretty much dead for about a year. Also PS4 failed to sell software. There is not even one million seller on Ps4. Not even FF, a surefire millionseller, could reach that number. Now PS4 is in a good situation still because there is no competition in the market but its not an incredible success at least in japan so far.