If your exhausting yourself at a desk for 8 hours x5 until complete burn out...well...then you go from writing 80% to 0%. How does that help the company? It really doesn't, and your overall average drops real fast (even though your not there).
Others maybe already get this (or live like it anyway) and spend less time typing code. Taking care of yourself so you can continue to contribute 4-5x of others is far more beneficial for the company in the long run.
Think about the "10x" companies - FANNG if you will - they have bicycles for people to go between campusus's, entire gyms, foosball, etc, etc. They seem like insane perks to the outside world, but it's what give balance to the 10x'ers whom work there - and they do it on company time.
Good luck!