I'd be willing to bet (a very small sum) that the HTTP 0.9 and 1.0 servers encountered are app servers/frameworks. They're simpler to implement than HTTP 1.1 an

I'd be willing to bet (a very small sum) that the HTTP 0.9 and 1.0 servers encountered are app servers/frameworks. They're simpler to implement than HTTP 1.1 and don't set expectations on the client they can't meet. When you've got a fleet of machines behind load balancers you don't need things like a Host field to support vhosts since it's one site to a host. You also don't need pipelining because each connection is a one and done operation.