External scripts are not a requirement, just an option, and it's quite possible to optimise pages without something like amp or FB instant articles.
The web is really well suited to content heavy sites, it's just being used to do all the things humans like to do (spam,ads,control over access), as gopher would be if it were popular. I think your problem is more with the behaviour than the medium and if you restrict the medium people would just look elsewhere.
The problem is with humans, not the medium; even plaintext can easily carry spam, pointless content or links etc and it's very hard to separate from real valuable content, in fact it me be considered both by different people.
The web is really well suited to content heavy sites, it's just being used to do all the things humans like to do (spam,ads,control over access), as gopher would be if it were popular. I think your problem is more with the behaviour than the medium and if you restrict the medium people would just look elsewhere.