If you compare the cost of inflation to the cost of higher education over the past 40 years, sure, it's probably in a bubble now. And especially if you compare the number of "free riders" decades ago(people who got their college fully paid for by someone else, mostly the gov't) to the number of kids taking on non-gov't backed loans from banks today, then it's not a pretty picture.

How can a bubble like this even pop? Kids aren't just going to stop going to college en mass.
Universities are not going to drop their tuition rates back to 1975 levels, and instead live off their massive endowment funds for a period of austerity.

The bubble that will pop is the sea of minority, non-traditional, vocational, low-income college dropouts who can't pay back their loans. Granted, the for-profit colleges got a bit too greedy in signing kids up(thanks US gov't for providing subsidies to encourage them!), while the banks, as is typical of their particular species of shark, were only too happy to over-extend cheap credit to kids. I would be interested in knowing the total amount of outstanding private loans at for-profit colleges. Because whatever that amount is, Wall St. better prepare for all of it to be written off as losses without the need for Federal bailouts and financial shennanigans.

Let's forecast: America has the weakest labor market since the Great Depression, record unemployment, with no end in sight. Like an article I saw just yesterday, right now, today, America would need to add 270,000 new jobs per month, every month, until the end of Obama's 2nd term in office for the employment levels to return to what was normal pre-2008.
And that just ain't going to happen, no matter how much Hopium you're smoking, and no matter what fairy-tale of cognitive-dissonance that you've chosen to believe in.

Unemployment for those under-25 is at a historic high. Wages are probably not rising. The entire business market is now stuck moving sideways, and it's going to be that way for at least a decade(the US is the new Japan). At least 50% of all college kids never even graduate, and the rate is higher for kids attending for-profit colleges.

So where are all these kids going to be working when they either graduate or drop out? They won't be able to pay back the loans. And that is going to trigger the popping of the bubble. And much like the way the housing market explosion threw off a ton of shrapnel and hit targets nobody even thought were in the line-of-fire, a similar thing will happen here. Most of these college loans have co-signers, who are mostly the parents. So it's not going to be a bunch of bankrupt kids—it's going to take down the lower-middle-class with it.

The true tragedy becomes apparent when you compare America to Europe and Latin American nations where the idea of paying for college is as foreign as the idea of paying for health care. Education costs are simply built into the society through taxes, instead of being externalized into a sociopathic, inhumane, capitalist tragedy of the commons extraction of profits like we have in the US. Instead, the US chooses to piss away its wealth on military spending and Wall St. gambling.

tl;dr version: The banks are continuing to wage a covert war against the middle and lower class, exploiting them into permanent poverty through loans that simply can't ever be paid back. The banks have the law, the gov't, and armies of finely suited lawyers and scary storm troopers packing guns on their side, the poor have well, nothing. The class divide in America is about to widen even more starkly. If you're already rich, or your parents are rich alumni, or you're in the top 85% percentile of income, or in a white collar profession, you won't even see this bubble nor its popping. If you are on the other end of the economic spectrum, it's going to wipe out you and a lot of families like you. And it sure is a great thing that these poor families are likely already underwater on a home mortgage loan.