The trouble is of course the huge legacy of all the existing sockets you’d have to replace, never mind the pure unpopularity with the public of switching standards.

Possibly the most successful attempt at convergence so far has been the Europlug, but only because it’s a weird compromise. Did you know the europlug prongs aren’t actually parallel? They angle slightly and have a little flex, so they can be accepted in multiple European countries’ sockets that actually have slightly different dimensions! It’s a cool design, but you wouldn’t intentionally design it that way if you had the opportunity to standardise the world from scratch.