This is 100% my view of it. A program that's VERY successful becomes a license to print money, almost. Bama's been paying Saban & staff a ridiculous amount for a decade, but have gotten that money back several times over. As NDRock points out, losing and having to keep paying bad coaches to go away isn't cheap.
NOBODY, not even Texas or Bama, has the potential to be a true national team like ND could be again with over the top success. A willingness to spend what it took to be the best would likely return that investment several times over. Bama has picked up a few million casual fans across the country who love college football but don't have a successful local team or alma mater to pull for and get behind. That's translated into tens of millions in additional revenue. ND's ability to tap into that market if winning 11 or 12 games per year, going to the playoffs consistently, and winning it all every few years would dwarf Bama's share of that market. And that sort of national awareness soon translates into national recruiting success too.