There are broadly two "fair" models of wage compensation - equal pay for equal work and equal pay for equal results (of course there are other models - equal pay for equal skin colour, unequal pay for unequal gender, etc. - which we shall condemn
ab initio as unacceptable and counterproductive). The first one applies more in the production context - workers on the shop floor should be paid equally if they produce the same results, independent of which product actually sells better in the market. The "fairness" of this system lies in the fact that factory workers normally do not have much control over the marketing and revenue generation aspects of the business. Their job is to produce and produce with quality / without wastage.
The second model applies more in the service industry context - those who generate comparable client profitability should be paid on par. Consultants, investment bankers and others are often compensated based on actual results and much less on the number of powerpoint slides they created. Their job is to generate revenue and profits while keeping rules and regulations in mind.
Which model applies to professional sportsmen? This
Bloomberg article uses the Tennis example to say that equal work should generate equal pay. If you play 5 sets, you should be paid more. I find this argument ridiculous, because I favour model two above for professional sportsmen. If you generate higher spectator interest resulting in higher match audience, television viewers, etc., you shd be paid more. There was once a time (late 80s, early 90s) when women's tennis was often more interesting to watch because Ivan Lendl and Mats Wilander were the leading players in the men's circuit! In such a case, the women should be paid
more than the men are. Most early round women's matches are much, much less interesting than early round men's matches. Shouldn't men be paid more to play those early rounds?