I'm reading Computer Networking: A Top-Down Approach, and from what I understand, UDP has no widely adopted mechanism for congestion control like TCP does. Isn't this a problem for the Internet as a whole, considering that the upcoming HTTP/3 is based on UDP?
I found DCCP, but it is not widely adopted.
And I know congestion control can be implemented in the application layer, but why would an individual choose to do that, if no one is required to? Congestion control seems like something that is good for everyone if everyone does it. But it is not required, and it seems that a few people doing it on their own only results in their application being slower without any noticeable benefit to the Internet, if everyone else doesn't care about congestion control because they just want the highest speeds for themselves individually... which results in a slower Internet for all. This seems like it will be a problem as UDP is more widely used in the future.
Am I off in my understanding of this?