Usually, people bankrupt out or sell assets, creating a cascading effect (lots of bankruptcies or lots of selling). That ends a bubble. But student loan borrowers can't do that - they can't get out of the game via bankruptcy (student loan debts will even be extracted from your social security payments, should that be required), and they can't sell the (possibly overpriced) asset they bought, a university education. There's no exit possible.
So for current borrowers, they're totally trapped, forever. Leaving the country is their only escape, which itself is difficult. Many of them will spend their entire lives, from age 18 until they die of old age, on the edge of poverty with an unpayable loan balance looming over their heads. The bubble can't pop! The only way there can be a pop is if they all commit suicide at once.
What it can do is slowly deflate. What this looks like: an entire generation decides, possibly through seeing the suffering endured by their parents, that college is a bad deal. "Son, don't make the mistake I made." They stop going. No borrowing, no college attendance.
My prediction: emigration and noticeably lower college attendance in the future.