I don't think it's all that common. In my case, I was laid off by a west coast tech giant and actually got something of a severance for the first time in my life. Instead of finding another job right away, I bought a used school bus and converted it into a motorhome. Since I thereby already knew how to drive a big bus, getting a job as a school bus driver was a natural progression. Mainly I do it for the health insurance which is otherwise pretty useless and insanely fucking expensive.