.us didn't take off for several reasons, already discussed at length here.
Among the reasons is the fact it was released late to the public (2002) and .com is dominant. Also, the US is in a unique position as it 'owns' several other extensions: .mil .gov and .edu is mainly American. So unlike other countries, the US cannot be 'mapped' to just one ccTLD.
Bottom line, releasing another TLD or let's say sTLD like .cat, wouldn't be successful. It's too late now that the landscape is set, and that's why nTLDs are struggling. People either go with .com or ccTLD, or both.
As for the geoTLDs like .wales or .berlin I don't think any of those are really successful, as they are competing against powerful national extensions.
.cat may be doing better but it's because it wants to break away from Spain and .cat is the next big thing to .ct. Understandably a lot of people there are eager to distance themselves from Spain and .es.
However, what I have seen in Barcelona is that .es is used most often, followed by .com and then .cat. So .cat gets some use but it's often by official bodies. I have noticed the same with other geoTLDs. It appears that official/public entities are pretty much the only visible end users.
Back to the US: we now have .nyc. Again I don't think it is really meaningful. Even though NYC is big and has an identity of its own, it can only be a niche extensions.
So there is not point adding thousands of strings that nobody will use for anything serious.