Part of hosting is in the corporate world, where things are slow to change. One major client I work with gives the option of Java or PHP for hosting -- and until recently that was only PHP 5.2.
And that leads into the deployment issue, where PHP is really the only major platform where an Apache module is a viable option. (Yes, mod_perl and mod_python exist; the former is painful in my experience, and I never hear about anyone using the latter. Then again I've never been a Python guy, and I find most Perl work painful anymore.) Everything else either uses CGI (slow), or uses a separate application server architecture, with inherent complexity. With that sort of architecture, having someone who knows what they're doing is necessary, but that doesn't make all the pain go away.
I'll be interested to see if Node.js, or something like it, ends up going more toward the PHP-ish route, or more toward the Ruby/Rails-ish route. (Ruby and Rails are already more on the Java path.)