[cg505]

There are a ton of networks (think big corporate networks, schools, shared apartment wifi) that enforce too many weird port restrictions. Many of those places rarely get network or config updates. I don't think it's as bad as IPv6, but there are a lot of people for whom it isn't going to just work out of the box.

[dathinab]

Sure, but for that people a non small part of the internet is already broken. Like websockets being broken and in turn slack being broken.

[patrickmcmanus]

websockets is carried on TCP. Often bootrstapped on HTTPS tcp/443.