Isn't that just a truism of the Pareto principle? Is there any field where that's not the case? 20% of lawyers make 80% of the money. 20% of doctors make 80% of the money. etc etc.
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).
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).