Configure your web server in any language you want (so long as it has sqlite bindings).
Serve your web pages from any back-end you want (so long as it has zeromq).
Has it turns out, zeromq and sqlite are low barriers to entry for any language.
You're right though, in that you can do all of this with apache, if you're willing to write the right config generator and install (or create) mod_*. Mongrel2 just makes it easy.
Configure your web server in any language you want (so long as it has sqlite bindings).
Serve your web pages from any back-end you want (so long as it has zeromq).
Has it turns out, zeromq and sqlite are low barriers to entry for any language.
You're right though, in that you can do all of this with apache, if you're willing to write the right config generator and install (or create) mod_*. Mongrel2 just makes it easy.
edit: Also, what zed said :)