Not sure what to call the volumes but you could store them in a modified tape library - without the tapes
That would change things for employers immediately.
But that kind-of assurance would be hard to give within the context of online course with form-based tests, however challenging the tests are. Someone who can absolutely anything online might still not have the social skills necessary for many jobs. We hope that someone who's done four years at a good school has absorbed some social skills. If there was online way to actually guarantee that a person has abilities that an employer wants, then online could win.
The other side of this is how quickly business in general becomes nothing but online interaction. The sooner that arrives, the sooner ability to interact well online will become the main qualification and thus the sooner an online degree will have prevalence.
There is a well-known tendency to overestimate change in the short term, and underestimate it in the long term.
Even as I was predicting that this could have huge effects in posts yesterday, I say this fully aware that it won't happen next year, or the year after, or the year after. And even then, the inflection point I would look for is not "when nearly everybody goes online for college" but "when nearly every employer will accept online degrees as sufficient for employment verification", which is almost certain to happen many many years before a shift.
On that note, I completely disagree with your claim that all four groups need to move in sync. Only one group needs to move: employers. Once that happens, all the incentives will be put in place for the rest to follow in turn.
And, ultimately, that's my argument. Undercut the current universities by a full order of magnitude or more on price, and you completely realign the incentive structure. It will take time for society to adjust to the incentive structure, but it will be as inevitable as the move to cities when it happens. (And moaning about it about as productive as moaning about the loss of "small town values" as humanity keeps moving into cities.)
It won't happen in this recession, but it very well could happen in the next one. And if this one drags on for long enough... this recession has certainly had the effect of precipitating a lot of things that we've all known were coming for a while but expected to happen in the "indefinite future", with the definite future happening somewhat unexpectedly definitely in a nearer term than we thought. (Newspaper industry crashing, numerous industries facing rather more immediate results of bad decisions on pensions, the automotive and local governments most visibly, etc. All things that many people could see coming, but expected to be able to put off longer.) If this recession drags on for long enough the higher ed bubble could pop far sooner than anybody today would be willing to predict. Including me. I'm not predicting it, merely leaving the possibility open.
(I do think the next ten years are likely to end up more socially chaotic than the past ten or twenty would lead us to predict, and I don't mean 1960s-style social chaos, but chaos as fundamental institutions are broadly rewritten. A higher education bubble pop would be merely one part of that.)