PHP won because you just wrote the code and it worked. With Perl you had to deal with the cgi interface which was a pain. Mod_perl came later. PHP was just extremely easy to get started with — you did t need to really understand Perl modules, the cgi spec, or anything to get started with it.
I gave up on PHP around 1.8b6 or something like that. However, before mod_perl arrived, I have used Perl to generate PHP code: a minutely cronjob would read the database and generate the PHP code with the right pulldown values from the database. It was the best of 2 worlds: a sane programming language and fast (non-CGI) execution.
