I remember a quantum information theorist went to become a hard labourer in construction because he thought "physical labour is food for the soul"
I don't think this is a case of "grass always seems greener on the other side", but of getting a job as a quantum theorist. It is hard to find (and keep for a long time) a job in your area of academia. :-(
https://scottaaronson.blog/?p=5730
Stephen J. Wiesner (1942 – August 12, 2021)[1] was an American-Israeli research physicist, inventor and construction laborer.