I don't know why you are being downvoted, this is a very legitimate question. These server-side frameworks are all alive and kicking and very competitive. When some other smaller ecosystem comes up with a good idea (like elixir/phoenix) there is a rush to replicate which happens rather fast.

I think in the end the competition will lead to specialization. Python will almost certainly capitalize on its data science / ML links but its not clear (to me at least) how php and ruby will differentiate themselves.