Working at bigcorp for 14 years so far and I struggle to think of a single day where I didn't need to consider algorithmic complexity or efficiency. Do you not write code that fetches things from a database? Do you not need to make tradeoffs between how much data you fetch at once, which fields you load, which things you cache, whether your query joins on the db or materializes things separately, whether you lazy or eager load, whether you are doing a O(1) or O(n^2) lookup and the tradeoffs, whether you can use a db index or not, memory/latency/compute/storage tradeoffs, etc? I feel like in even a simple bigcorp SAAS you need to consider this stuff daily.