Why should we cut out PS2? Why does it deserve a special exception other than being extremely successful?
I don't agree that Xbox exiting the market will radically help Playstation (and also they're not exiting the market). There's only 10M Series X in the market. If Playstation 6 sold 150M it would both be the most successful Playstation, and still represent a low rate of growth since 2001.
The cost and scope of software is growing much faster than the growth of total console ownership. That doesn't mean Sony and Nintendo stop making consoles, but it does mean publishers need to look beyond consoles for growth.