> What happens when there is a better USB-C plug
EU laws are not like physics laws, you can change them. That's why so many people are employed in policy and law making.
So if it happens that in the land of cable freedoms they come up with something much better, it would be adopted. At first, those electronics which can accommodate more than 1 type of charging plug will start getting this new plug alongside with USB-C and if there's actual demand for it they law will be changed to allow only that plug.
I don't know how much if this is about environmental concerns, I'm under impression that EU is never happy about rent seeing companies and tries to standardise everything. That's probably why it's going after browsers and App stores: it expect company products to be picked for competitive reasons, not compatibility reasons. Another example is EUs enforcement of standardized EV charging plugs, arguably Tesla plugs can be better but overall it's better for everyone to be able to charge everywhere even if it was possible to have slightly better charging plugs on some stations.
I imagine, the US citizens are confused by all this due to the nature of how EU and US function. With GDPR, the American audience was imagining that startups will go bankrupt when trying to comply with EU law and there were tantrums about some people abandoning their projects because they don't have resources to deal with EU regulations. Maybe it's because how lawsuit happy the US is, maybe it's because how the laws are enforced in US is different than most of EU - I don't know, but in general Europeans feel differently than Americans about the government involvement.