But problem is places with lots of devices, then would need power strip and might as well use AC one.
The problem is appliances that draw too much power for USB-C. They also draw too much power for 48V DC. There isn’t any advantage to switching the wall voltage.
Leviton makes a 60W unit now that supports PD. Be warned it's a little janky in that it tries to be "smart" and re-negotiate (well, outright drop to 5V) the port if your device stops drawing substantially less current than requested. This can confuse some devices - especially those without batteries. Otherwise I can say the 20V/3A profile works fine on my macbook.
I don't think anyone would switch the wall voltage altogether; not in one generation, at least. But a majority of the devices we plug into AC outlets these days convert that power to DC before doing anything with it, and a majority of those devices do so using USB; so one could imagine that a house which had solar panels and batteries could also have DC power wiring and dedicated USB-PD receptacles, skipping the inverter and all the rectifiers.
Also, the DC voltage for house wires and batteries need to be much higher than USB voltage so will need conversion. Might as well have it be AC to DC converter.
There is a problem connecting solar panels to batteries and needing two inverters. But that could be solved with higher voltage DC between them.