I think PHP is way more accessible syntactically, even with all the standard complaints about the language. In the early 2000s it felt like "simple C style function calls embedded in HTML templates" more or less. Not much to have to teach there.

And serving it tends to be "copy the files to your web server's public dir".

Perl is a very difficult language. PHP was a comparatively simple language. PHP was just a scripting language for C and incorporated as many open source C libraries as possible back when open source libraries were a bit of disjointed mess.

PHP's success and Perl's decline was obvious at the time.

PHP is, at least for me, way, way more readable. Similar enough to Java that you don't have to re-learn syntax too much.