I'm not a semiconductor engineer so I could be totally off here but. My guess is that for AMD and likely Intel the reason the IO die is so large is because of

I'm not a semiconductor engineer so I could be totally off here but. My guess is that for AMD and likely Intel the reason the IO die is so large is because of all the PHY's on it (DDR, USB, etc) which would give a minimum size of the IO die for chiplets. Which if true explains why you wouldn't care as much about the process node for the IO chiplet as it has a minimum physical size anyway.