I think it comes down to scale. If you are running your application on 5 or 10 or maybe even 100 servers, buying a few more to handle the inefficiency makes so

I think it comes down to scale. If you are running your application on 5 or 10 or maybe even 100 servers, buying a few more to handle the inefficiency makes some sense. But if you code needs to go on 1000s of servers or more, it's probably worth paying people to optimize it instead of buying more hardware.