These boards support Intel 12VO power supplies.
These boards support Intel 12VO power supplies.
The 8 pin EPS CPU connector would stay the same. The 24 pin ATX would differ. However, based on your inquiry, I don't believe that. The ATX 3.0 PSUs appear to be quite delayed, with only a few manufacturers mentioning them. The PCIe Gen 5 connector on next-gen cards seems mostly confirmed. Regardless, I wouldn't upgrade my power supply anytime soon.
If a motherboard maker wishes to, they can choose any chipset, not just the two available. The main change is adding DC-DC converters for 5V and 3.3V since those are no longer supplied by the power supply. Regarding the advanced PCI-E power cable, there will be many adapters for older power supplies, eliminating any concerns.