CPU socket is not the only thing that has technological upgrades.

You’d still be locked to a certain DDR ram, PCI etc generations.

Imagine if they had made a LGA MAX socket during the DDR2 era. How would a 14th gen perform with DDR2? Or how would your RTX 4090 perform in an ancient PCI slot?

Just cover the whole mobo with cpu pins to be as future compatible as possible :D

Athlon XP 2500+ => I7 2600 => I5 6500 => I5 12600k

Basically, whenever the performance jump is huge enough so that I can justify the expenses of upgrading.