I think this thinking is exactly how it gets past testing. You could force every engineer to have a CPU meter, but that alone won't help; they'll ignore it, assume it was a coworker's change that made the usage higher, or just assume their CPU is high because of their 30 Chrome tabs currently open while developing.

A better solution would be to have CI monitor CPU usage so that increases/decreases could be monitored and reported over time/per commit.