I agree PS5 will keep flopping in Japan
Will get all the games regardless. There is no reason to not port their games to PS5. Bigger userbase = More sales. With Switch being the lower factor in mind upgrading it to every other platform is going to be easy
And the big-budget games will still get released on PS5 because PS5 is smashing outside Japan, so Capcom and Square have nothing to lose by making their AAA games to skip Switch and focus on Playstation/Xbox/PC crowd, for Switch they will release smaller budget games until Nintendo decides to release a more powerful console
This will prevent PS5 from complete irrelevance, there will always be a small market for Playstation (5-6 million at least)