Where did the money go from all of the sold out stadiums and the gear that was sold? Did Ty Detmer see any of that? Probably not as much as he earned. Lucky people were profiting off of his success. If he got paid for use of his name/likeness and he used it for a car and a down payment on a house i'd much rather have it go to him than someone else that wasn't as directly responsible for all the success and the fame and interest.
Same thing for Jimmer. Theres no reason he shouldve had to drive a crap car when he lived in Provo or live in a crap apartment. Theres no reason he should have come out of college having to worry as much about money. When you are the biggest college basketball star in the nation you are worth something and you are making money for a lot of other people but you.
As to whether it gets messy for the church...seems like the church has never complained when people earn money.