The difference I think is if 80% of professional musicians can't make a living & it's not clear that's actually the case (i.e. streaming isn't the only source of revenue). Similarly, music may have a higher "stickiness" for tenacity where people see it as a higher calling for them even if they're not making money (vs someone not cutting it as a lawyer/doctor to even pay the bills is going to quit & find something else if they weren't even weeded out during school).