This question is coming up a lot these days, but the nation's best minds (New York Times, New Yorker, Washington Post) are swinging and missing. ... My own belief is that educational quality is the next great frontier. If we can put a man on the moon in the 1960s, surely with four years and $120K we can turn a reasonably able and motivated 22 year old into a critical thinker who can reliably communicate, collaborate, gather facts, assess data, lead, follow, and approach problems with both empathy and objectivity. Further, improving quality changes the debate from "how much does higher education cost?" to "how much is higher education worth?" And if the worth is sufficiently high, both public and private employers would be willing to subsidize it in exchange for preferred access to graduates.
The only barrier is institutional focus. To make this happen, a university has to take an "Apollo Project" approach that focuses purely on education. After figuring out the "how high" and "how fast" possibilities, an institution could then focus on controlling costs through process improvements and building modules. First quality (worth), then cost. This is not trade school education; this is about fully exploring human potential.
The first university to break into this space will have a profoundly disruptive effect the rest of higher education. The future of higher education is education.