Such an ownership model is certainly not suitable for the examples you bring up. One simple modification that might work for the pro athlete case is that the athlete always owns 70% of the company, and the rest of the team get ownership based on time spent. Or you could even allocate percentage ownerships to each division of the company. The PR team gets 15% divided amongst themselves based on time spent, the health team gets 10% etc, where the percentages are based on some notion of the value generation by each team.

The proposed model, I think is best of large companies with lots of workers - say a factory, where most people bring in roughly equal amounts of value. The high value people could negotiate earning ownership at 5x or 10x the base rate, for example.

The big point is that there is a massive space of possible ownership models and exploring them is a very interesting exercise. In fact, experimenting with such models is an excellent way of exploring and understanding how much value different people in a company bring and what they are worth.