Not a perfect analogy, but PHP was on its way out for a while and probably would have gone all the way out -- if it had not been for one very high-profile company that essentially made it usable at scale. And the reason it did so was because even though PHP had little cachet, it was easy to hire PHP devs. Similarly, there are now a lot of things you can achieve with vanilla JS (or even vanilla CSS) that you used to o…
I would argue that Facebook's work had little impact on the "scalability" of PHP. I don't see people adopting HipHop (HHVM) in huge numbers. The problem with PHP was it's standards body wasn't doing a good job of keeping the language consistent and it lacked a package manager where Ruby, Python and Node all had solid standards bodies and it was driven by having package management. With Composer that changed and it ap…
What came out of it was PHP 7 and the gap closed significantly. There were even rumblings about a PHP JIT complier. So I would say the impact was a good one.
As for PHP growth, what's there to replace it? Golang, Exlir, Node, Crystal, Ruby, Python? They all have their own pros and cons.
With laravel being a great framework and much easier for developers to use rather than symfony. I would say the future of PHP has never looked better.