fh wrote "In short, my point is that if a new convention is clearly better, it's usually possible to switch gradually, and that this is usually done."<p>I'd love to see any data at all about this. Or even a few not cherry picked examples.<p>You also wrote: "The electric plug situation is rapidly improving".<p>I have seen zero evidence for this. I've yet to travel to any other continent without this being a problem.