Without any numbers, I wouldn’t call Returnal a commercial failure. Don’t know what people expectations were for the type of game it is. Even if the game is close or above 1 million units, Sony would be happy with only 9 million PS5 units WW.
As for Part II, is clear that it lost a “lot” of the original fan base, but it’s also clear that it GAINED a lot of new fans, A LOT. But I’m pretty confident the game is between 10-15 million units sold by this time and Sony are pretty happy about it despite the tons of backlash they received when the game launched.
As for Death Stranding, the same, people expected something else. A failure? Again, without numbers I can’t say if it was or not.
I’m finding a bit contradictory that some people complain about Sony not delivering new experiences and different experiences that made Sony “different”, and when they release the different experiences, players don’t support them.