A lot of sports clubs are run as private businesses. In a lot of cases the money the club makes from the player vastly outnumbers what the pays him. I could be spouting bullshit here but currently Bale is the most famous player in the prem he is worth a lot of money in advertising (he is currently the face of lucozade. I read somewhere that madrid will be getting his image rights to use, if madrid see that as being worth more than £300,000 a week then they should be able to choose how much to pay him. Just to be clear I do think the money footballers are paid is ridiculous but at the end of the day they help thier clubs make money and these are private businesses. You have more of an issue with the amount that many of the higher ups in the government and nhs earn.