I did not talk about Thunderbolt 4, what I was asking is if doing without a pcie x4 slot (instead of using it for an ssd) through an external extension cord it is possible to insert a PCI 2 x16 graphics card, this allows you to have a laptop maybe a very light ultrabook that if connected to a fixed location can provide a power comparable to a fixed.
The fact that PCIe switch/mux heat up I don't see it as an extremely serious problem since they could be placed outside the laptop (maybe in the case of the egpu).
This would in my opinion be very useful in niche environments, both for casual gamers and for professionals who need to have an extremely portable and efficient device on the move but with high power in a fixed location when needed (other than apple ).