"What if royalties from broadcast radio-play was divvied up like this?"
A business with a radio audible to customers needs a public licence - apparently even if it is only the sole car mechanic's radio in the workshop. If they want to play their own choices from recorded music then the licence for that is more expensive.
The royalties from that music licence will be split in a way that is totally unconnected to the tracks which are heard. Presumably the proceeds get distributed to artists on the assumption that the most popular ones are getting the most plays.
Or do they count each licence according to employees/customers social groups and their likely listening preferences?