There are tons of possible ways to make things work. When BYU negotiated its current ESPN deal, BYU's long term schedule had very few marquee games (BYU was still in the MWC). Now, BYU has some very exciting marquee games on future schedules and TH has proven he can get more. By the time BYU renegotiates its ESPN contract, assuming BYU is still indy, BYU will be able to command compensation in a similar range with the Big 12. Let's face it, those Iowa St. games are not worth much. BYU will be playing some marquee games against the likes of ND, Stanford, USC, other PAC 12 schools, Wisconsin, etc. I assume most seasons will see 5-6 P5 schools on BYU's schedule, plus games against the best of the rest like Boise St., NIU, etc. With games like that, BYU will command much more cash from TV than it got last time, and it could be more than the average pay out to many teams in P5 conferences.
If cash is the hang up, few schools offer a better financial picture than BYU and that financial picture will only get brighter with time.