Thinking about it, the SoC idea could stop at the southern boundary of the chipset in x86 systems.
Include DDR memory controller, PCI controller, USB controllers, iGPU’s etc. most of those have migrated into x86 CPU’s now anyway (I remember having north and south bridge chipsets!)
Leave the rest of the system: NIC’s, dGPU’s, etc on the relevant busses.
Thinking about it, the SoC idea could stop at the southern boundary of the chipset in x86 systems.
Include DDR memory controller, PCI controller, USB controllers, iGPU’s etc. most of those have migrated into x86 CPU’s now anyway (I remember having north and south bridge chipsets!)
Leave the rest of the system: NIC’s, dGPU’s, etc on the relevant busses.