"Degrading Performance" arguments are bollocks. There needs to be evidence of that, and also of measuring impact. PS3's versions of many games, particular on UE IIRC, were well below XB360 performance, but the titles and machine still sold. You'd have to make games soooo bad to make a difference, not just 20% less pixels, and then your game would stand out as shit because all the other games are showing the rival's console at its full capabilities. It'd be mind-numbingly obvious the poor game would be because of the poor development, not the platform. Like, we can look at TLOU on PC and think "looks like Sony are trying to make the PC look bad," and that'd be a clearly dumb move, destroying their reputation and massively harming sales of the title. At no point do we (other than die hard Sony FBs) look at TLOU and think, "wow, PS5 must be amazing." Certainly not the wider populace to drive PS5 hardware sales.
If you are releasing a game, it's to maximise investment, which means doing the best job you can. This argument of wilful sabotage is such a schoolboy playground level of logic!