You could, but you'd be ignoring the realities on the ground:
Wordpress powers a vast chunk of the web[1], whether we like that or not, and frameworks such as Symphony a good bit of the remainder.
For the love that Clojure, Rust etc get on HN their over-representation should not lead you to believe that 'PHP has had it's shot', PHP hasn't had it's shot by a long shot...
The reasonably good news here is that PHP code tends to have a rather short life-span so the bulk of it should die off relatively fast once there is an actual alternative.
That's the puzzling bit: even Ruby, python and all the other 'better' languages still don't have the deploy situation worked out to the point that PHP has.
