Nobody except central banks can survive with wasting of money, so it is profitable investment from their approach and for some time it will be (tv rights prices grow at high pace as well, price of tickets go up as well etc, bilions of people want to watch just the top teams and top players etc... so there is still space).
The another view is to look at it from the point of view of society or humanity, but that is not the point of view of the market, so it is pretty much irrelevant. I personally made all my money through sports (betting, affiliate...), but I never understood why people watch sports or bet on it. When I was young I used to be a sport fan and casual losing bettor, but it is like past life that I do not recall. So I do not know why sport stars are so valued by people, that their price is in billions, but some fact have to be rather accepted and not explained I think.
People are generally very nonindidivual creatures that create hypes and bubbles, because their desires are copied from other people and spread like viruses (for example a desire to see the best soccer player). So this is why occur events like steep grow of prices of sport players, houses or bitcoins.
If you talk to God, you are praying; If God talks to you, you have schizophrenia.