Earlier quoted context omitted.
That is literally how php does. Let's fire a thread for every request and block on db reading or any action that require io. And it seems it works (at least for php)
.NET is meant for stuff like microservices; you don't see lots of those written in php, right? Also, for high-traffic websites, that's really not a great idea. You might say "but Facebook, PHP" - I'm really certain that their current codebase doesn't have a thread that blocks on DB for each user request.
I'd be willing to bet more projects have been killed by trying to architecture for performance up front than have been killed by being too successful for their own good and keeling over.
If Twitter could make it past the Fail Whale days, I think most of us can too.