Learning productivity tricks and building tools actually lets you do the same amount of work in less time. Some quality initiatives reduce rework, which also increases throughput. And these practices also reduce stress during exceptional events (production issues). That effect may be mostly obvious but what we don't ever talk about is the fallout of stressful events and how they affect the quality of the code produced immediately afterward.

Burnout, as you say, is the end game of not doing this. But I think the symptoms are detectable long before that point (and I might argue are part of the feedback loop that leads to burnout).