It’s a balance though. While of course having every single appliance have the same types of plugs has significant benefits, on the flip side power outlets haven’t evolved in almost a century. Think about how much nicer it’d be if they’d been allowed to evolve to say, be safer, smaller, deliver networking, work the same all over the world etc.
Writing a specific standard into law has downsides that USB-C proponents never acknowledge. While I’m personally glad iPhone switched, USB-C is absolutely worse at its main job, being a charging plug, than lightning was. And we’ll be stuck with it for decades because no one has incentive to develop a new one anymore.