For years, many people have argued that one of PHP’s big successes is deployment. The language has little to recommend it for anything beyond simple database-backed HTML templating, but there’s little easier than dropping a couple of .php files in a directory through FTP.
While there are still millions of wonderful (and ultimately unproductive) flamewars about how mod_php is faster than vanilla CGI Perl and Ruby uses too much memory and FastCGI is unstable and shared-everything on a monster JVM is obviously more scalable, none of that will ever matter to most of the deployed PHP code in the world today.
I still think in Perl, but as an only occasional programmer, I seldom find it the best tool for the job. The Perl community failed to successfully colonize the new ecosystems of programmers who don’t have root access. Simply asserting that PHP is linguistically inferior won’t convince anyone who has had to argue with a web hosting company about the load MovableType was placing on their servers.
mod_perl is great for what it does, but it’s clear that mod_perl isn’t what hosting providers most wanted. A slim Perl distribution — including perhaps a new Apache httpd module which only embeds Perl — with a good templating module, the DBI, and perhaps an XML parsing module or two could have put Perl on more $4.95/month hosting plans. The corollary to that of course is an easily installable bundle of Pure Perl for an application.
Ceding the very low end of a technology to an upstart is just one of the ways to let distruptive innovation eat your lunch.
One flaw in this argument is that approximately zero webhosts supported Ruby before the Rails lovefest. As well, the Rails deployment strategy went through several iterations. Here’s the interesting point which subverts my argument somewhat: Rails hosting suddenly became lucrative enough that several Ruby-friendly hosts appeared.
I haven’t yet figured that out.