This is a common straw man; PHP 5 and 7 made large strides, but that's because there was so much to fix, and there still is and will continue to be, like lack of first class functions, actual modules, etc. PHP is also unsuitable for persistent processes like serving WebSocket.
Why do you need "actual modules"? I feel that (when PSR-4 is followed) PHP's code separation practices are among the best, especially compared to other interpreted web-languages (Python, Ruby, js). And it's convenient while experimenting that it doesn't really enforce anything.
Without modules there can be dependency hell: conflicting subdependency versions, unless all your dependencies update their subdependencies in lockstep.
Websockets are no problem with Ratchet. OhDear is a high traffic app that uses laravel-websocket (based on Ratchet) with absolutely no performance issues.
