@0 If you are talking about jquery, google tag manager, etc, not really. I mean, not by themselves.
jquery minified is about 100KB. If you talk about fonts, like fontawesome, or other libraries that are used for transferring data using ajax or something, I don't know. Maybe. But that's because they transfer that data.
The problem is when you use too many of these in the same site. If each one of your scripts weight around 100KB and you depend on many of these, it's true that your site is going to go around the 2.5MB mark really easily.
One of the most bloated sites I know, which is a national diary, weights only about 5MB, and I tell you this one is bloated to hell with all that stuff. And some of the scripts weight around 100-120KB. In total, all these increase the size way more than it should. Yes, it's bloated. This is real bloat.
So yes, as I said, I can't ignore this problem.
However, blaming JavaScript or the protocol, like most people does, is not the solution.
@proxeus Personally I think that it would be better to go in the other direction and have an extremely limited protocol with homogenous styling like gopher, because in the majority of cases the main content of a webpage is non interactive. Everything else could be a desktop app.