We should stop thinking about the trade-off as between developer time and CPU time. The CPU is an inanimate object which doesn't mind pushing around more electrons. What we're really throwing under the bus when we optimize for developer time is the customer's time.

If an inefficiency saves a developer 10 days of work, but results in an operation taking 100 milliseconds longer, and you have 50M customers who do that operation just one time, then you've wasted ~58 customer-days.