For smaller sites, the number of parts often isn't huge, so boilerplate isn't a big deal.
Generating code in a Turing-complete language use a program written in another Turing-complete language can get messy.
Just because something is turing complete doesn't mean that a generator has to be able to generate anything possible.
If boilerplate is an issue, scaffolding / code generators can be a quick fix.
Generating code in a Turing-complete language use a program written in another Turing-complete language can get messy.