The demographic pyramid is inverting, interest rates have been falling but are now hitting 0, and the asset-owning bloc is falling below 50% of the electorate. Any one of these could stop the music, but all three are happening.
"You're lucky to get a home with a loan at a near-zero interest rate! We're such nice people. Uh oh, looks like your bank account just became worthless and your employer won't adjust wages to match inflation. And homes are even more expensive now! That's fuuuun."
The banks will get their wealth from somewhere, and the elites have proven that taxing by-proxy is much easier than traditional taxation and charging interest. If interest rates are low and the official tax rates don't go up too much, more wealth can be extracted and no one will be the wiser.
Besides, having everything on loan isn't really a sign of a successful system, depending on one's political-economic perspective. If everything is on loan, nobody really owns anything. You might be able to keep physical things on loan even if you fail to pay, but you will end up paying somehow. If his is one of the final steps in getting enough people to "buy" homes, that means we are close to a real estate collapse. It's serfdom all over again but with the illusion of ownership. (of course with property taxes for individuals we already have serfdom in that sense)