PHP is still the best for that type of website, I've done my fair share and that is an undeniable fact. Handles load perfectly, easy maintenance, works well with Redis/Memcached/MySQL, FPM+Nginx is solid, plenty of competent devs available and very very fast development times. What more do you want? It just work and it is not a clusterfuck of modules and libraries.
Front load everything with something like Varnish (Nginx can do some of it to a certain extent) and you'll be handling 15+ millions users a day on a skeleton server stack. Hell back in '09 Pornhub was running smooth on a similar stack with very few servers (when you consider the traffic).
If you ask me most of what was "invented" after 2004 is stuff invented by Google/Facebook who are realistically the only ones needing it, but they saw an opportunity to scoop up market share in dev so they marketed their stack as "bleeding edge". The only thing bleeding is my eyes when I see something that could be wiped up in a standard PHP/Python/Ruby stack but instead is made with so many dependencies and 3rd party library that you wonder if the dude who wrote it actually knows programming or if he just glued cool techs together because Techcrunch and HackerNews say they are cool.
But yes, the smaller players are usually using outdated stuff, then again 99% of the web is. Hence why Wordpress is still a thing.
And as a former Lead Dev of Pornhub, I can assure you that tech peeps definitely are aware of the bleeding edge of tech, just that most have a tendency to not buy the hype. My most recent experience still prove to me that 95% of the cool tech I see mentioned is pure mental masturbation, it makes life easier I keep hearing yet I've never seen it, always a mess, "Goddamnit Grunt!", "Fucking npm", 'Damn dependencies not resolving!", "npm is down", are so commonly heard nowadays I wonder if people who tout it as modern development practice have actually done any "old" school development and realised "modern development" is mostly vendor lockin and provides very little added value to a competent developer.
/rant