Because erlang is also built around that concept. Often when a server fails it needs to be brought up by hand and then wait until it can be brought back into r

Because erlang is also built around that concept. Often when a server fails it needs to be brought up by hand and then wait until it can be brought back into rotation (depending on how it's used &c). Additionally, some applications, like a database often only run on a single host (sure you have hot spares, but fail over is often manual and recovering is defiantly manual). So while I get your point, we're not going to throw out everything we have simply because it wasn't built around "let it fail".