I think MS would be content with 7nm S. 5nm is more expensive and chip redesign is not free. X on other hand would benefit from 5nm with smaller heatsink and lower power requirements.
PS3 YLoD is due NEC/TOKIN capacitors most of the time, not solder.
Earlier models could be overengineered to be more robust, but also have a known problems corrected in later revisions.
PS2 was designed to stream data to VRAM constantly.
PS2 does not have hw compression, but supports palletized textures.
GC and Xbox have hw compression afaik.
GC was limited by main RAM, but some devs used slow ARAM as a data cache.
It's just a cost reduction. PS2 and PS3 had like 20 revisions.
https://www.psdevwiki.com/ps3/Motherboard_Revisions
https://playstationdev.wiki/ps2devwiki/index.php?title=Motherboards