What do you think about those benchmarks? 4x, 10x faster?
Well, the benchmarks are quite real - the benchmark is done using LiteSpeed webserver 5.4 (which is rather "new") which got a big overhaul in terms of http/2 and https performance.
If we compare nginx to LiteSpeed webserver 5.3, then nginx and litespeed are a whole lot closer in terms of performance (LiteSpeed still being a bit faster at least based on my benchmarks as well).
For HTML files, one place where LiteSpeed does really well is handling gracefully whether the client asks for gzipped content or not - where nginx for some reason likes to store things uncompressed when using
fastcgi_cache, and it's kind of odd because you'd assume the webserver would be built towards the majority of traffic (which in many web applications will be compressed content).
People are always saying "LEMP is the fastest stack."
Likely because they haven't really been looking for the "fastest stack" but simply compare Apache and nginx, and then sure it's the fastest if you compare Apache and nginx.
Why these top-level websites don't prefer Litespeed?
When you look in the past, not only for webservers but also for other software such as browsers - it can take years before people start to catch up and consider using a different browser or in this case which webserver stack to use. There was also a long period of time where a far majority of websites would use Apache over nginx.
Big sites are often hard to just change software on, because you want to make sure that everything continues to work - downtime might be tons of money lost.
So because you have to invest time in it, it might mean that the benefits don't outweigh the time you have to spend switching to another setup, or maybe you want to change, but simply don't have the time or resources to do it.
But again, I think it's important to point out that LiteSpeed webserver 5.4 is rather recent, and that's where it's really killing the competition, and it for sure will take time before people consider the switch.
But it's for sure an interesting topic.
Personally, I think nginx got to the point where they feel they're the "top of the line" solution and the innovation/effort to continue to make it better is getting less and less.