I believe good architectures/stacks depend far more on the skill of the architects than the languages involved. Domain fit also matters.

As far as PHP, it's an ugly language from a language-only perspective, but easy to deploy and has lots of existing web-oriented libraries/functions. Think of PHP has a glue language for its libraries and some front-end JavaScript to improve the UI. Python and server-side JavaScript may someday catch up, but still have a lot of ground to make up.