Afaik, TeX is a Turing-complete language that can even read files from disk. Yet, it's only purpose is to render static text documents and nobody blames Knuth for inability to separate the presentation layer. The web is no longer a bunch of text documents. It's the first and only successful cross-platform solution. Moreover, it's still in the very infancy and in 10-20 years it will be the full-blown operation system layer on top of every platform. The problem of the web is that its sandbox has become leaky.