For some values of "real life". I don't mean that sarcastically... I mean that for many production environments (like customer-facing retail web site), I agree

For some values of "real life". I don't mean that sarcastically... I mean that for many production environments (like customer-facing retail web site), I agree with you. But that isn't the entire world. I've spent a lot of time doing hard realtime code. Often on limited-resource systems. (Oddly, its more difficult to get it right on resource-rich systems...) In the realtime world, it does require a certain amount of savvy to pick an optimal trade-off of run time, memory, and I/O. Hard realtime forces you to learn complexity analysis or die. You also have the luxury of a clear, bright benchmark for "good enough to ship", which shuts down a lot of purely philosophical arguments.