Just to expand on this, PHP started off as a templating language for html, grew into a functional language and then introduced OO.

Compared to Ruby or Python; both have been around for at least twice as long as full blown languages, they come from the opposite direction where web based libraries were introduced to them (rails, django etc).

So now a huge chunk of our web is running some really old PHP code, which is difficult to deal with; more in the sense it doesn’t follow established patterns laid by more complete languages which many don’t want to sort through vs any technical difficulties