I think its more of a trend we saw across gaming, there's much fewer releases but the games we do get are bigger and bigger. Sony saw an increase in sales per game that was probably above average, and I think that's maily due to being the only ones in the market delivering these huge budget story focused games. And with every release Sony's reputation for them grew and grew.I agree and disagree on Nintendo.
I don't think sales have changed drastically compared to the Wii, but that is with the caveat that the Switch is still an active platform. Wii had 3 games over 30 million (excluding Wii Sports) and another game not too far behind.