Not to mention that even when some components do shrink, it’s not uniform for all components on the chip, so they can’t just do 1:1 layout shrinks like in the past, but pretty much need to start the physical design portion all over with a new layout and timings (which then cascade out into many other required changes).

Porting to a new process node (even at the same foundry company) isn’t quite as much work as a new project, but it’s close.

Same thing applies to changing to a new foundry company, for all of those wondering why chip designers don’t just switch some production from TSMC to Samsung or Intel since TSMC’s production is sold out. It’s almost as much work as just making a new chip, plus performance and efficiency would be very different depending in where the chip was made.