If someone has a PhD in, say, the arts, and wants to start a new career in another field (due to scarcity of academic jobs) one obstacle is the automatic filters employers use to select for interviews. It used to be that a PhD was understood to have high level skills (reading, research, writing, speaking, teaching) that were transferable. However they are no easily filtered out unless they use the right words that the filter likes!
If, say, a PhD decides to do some event management type job, they are competing with 22 year olds with event management degrees or older folks with experience.
This is not unprecendented. I remember science PhD’s driving cabs in the 1970’s. I had artist friends working in IHOP or a grocery store. Some of them finally "made it’ after years.
I do think the specialization of degrees, the specialization of job postings, and the automatic filters are kind of siloing PhD’s into their area of study, even if they want to do something else. Or they can start in the equivalent of the mail room at age 30 and work their way up.