The program has enough money to pay for better coaching but is unwilling to do so. They have made huge strides but have still fallen behind the times.
To keep up in college football you need great coaching, facilities, and fan support. Even then it can be a crapshoot (Just ask Texas). BYU has decent facilities, decent fan support, but has fallen way behind on coaching. It is impossible to win consistently with bad coaching. You can maybe get by in the other areas, but not on coaching.
BYU has done what it can to improve facilities, done great things with media and fan access, and raised the general awareness of the program. Those things have been great and likely cost millions. But until they take their collective heads out of the sand and pay for some good coaching, BYU will never consistently return to prominence. Especially when you have Utah next door luring away the best potential BYU talent.
Swallow your pride. Pay for some coaching. It isn't tithing money, so don't worry about it. Untie Holmoe's hands when it comes to coaches. And guess what? You'll get a great ROI on your investment.