The reality is your average BYU grad is likely paying a full tithe plus a little more for offerings. Many are "traditional" households with a single income producer and a full time parent in the home caring for a higher than the national average number of kids. People can discount that affect on fundraising for the athletic department if they like, but it doesn't make it any less true. It's one of the reasons why the Church is far better funded than any other comparable religion because the average active LDS person (which is largely where BYU can expect donations to come from) gives a far greater percentage of income to charity than the national average. It's really not even close.

Now, with that said, I agree BYU can do better to get people to join Cougar Club at lower levels, especially among graduating students whose enthusiasm for BYU is higher, and it could do wonders to add a few million to the AD's coffers, but the luxury of having the average fan give thousands to the AD is one BYU will never have and I can live with that.