Players will nearly always need an agent of some sort to deal with the commercial aspects of their profession, same as bands have managers, companies have salespeople, etc. It's not just about how much a week, there's also relegation/promotion clauses, sponsorship deals, and everything else that puts money into player's pockets. Footballers play football, they're not usually entrepreneurs or business-savvy people, especially the younger ones. Also a lot of people are uncomfortable talking about money full stop, those people will always get shafted unless someone else is looking after their interests.
For me the problem is that football is now seen as a gravy train, anybody can become an agent, no qualifications are needed and it's bound to attract a lot of lowlife. On the other hand I'm sure there are some decent ones around, it's a case of spotting them and gettting them on board.