No idea what current viewership trends are.
If we are to believe the many, unconfirmed reports that the NBC deal brings in approx $15M/yr, ND is already well behind every other P5 team. As these deals are renegotiated in the coming years, we will fall further behind.
Live sports content commands a premium. As there are many more bidders today to serve this content (in addition to the usuals - ABC, CBS, NBC, ESPN, FOX - you now have Amazon, Netflix, Apple, Google, facebook, etc), the money is only going to go up, perhaps dramatically.
Maybe the estimates for the NBC deal are off. Regardless, I doubt ND will sit back and let this disparity go unchecked.