We're still doing that in the traditional web hosting industry.. while many are using cPanel and just scaling out X customers per server at my company since 200

We're still doing that in the traditional web hosting industry.. while many are using cPanel and just scaling out X customers per server at my company since 2007 and earlier we've done this using linux and load balancers for a long time for both web and email. Unfortunately however this mid-game between "traditional" and "scalable" makes it difficult to get people to move to a few things that would help which includes always using S3 so we don't need a central NFS server (which you lose a lot of performance to, even if it was just for some folders like the main code directories). And the reality is the majority of our customer base is on wordpress... and there are a lot of terrible wordpress developers which lead to all sorts of fun stuff. Also PHP in general reloading the entire code base every page load is stable though somewhat intensive compared to a Rails-style application for people that want really high hit-rate sites but don't want to make everything static - for example someone with a shopping cart. (We have had customers exactly like that, wanting to hit a badly designed wordpress site with thousands of people at once in a rush sale). So it is a thing.. but there are challenges. And honestly, surprisingly, getting people to move the needle a little from their basic cpanel setups is surprisingly almost harder than just changing platforms entirely because you have to educate people on how you want to be different to everyone else rather than selling a fun new solution.