Okay.
First I'm not sure about the kingdom being in "banqueroute". Mostly because, while being a distinct social persona from the king, it would touch at the crown nevertheless.
Second, the Etats Généraux gathering was a bourgeois AND noble institutions. In fact, it was an old Noble reclamation to have the king regularly asking the EG for his policy. It wasn't because of anti-bourgeois policy that Louis XIV didn't asked them by exemple (in fact, He, more than any ruler, helped to their rise) but because it would give opportunity to the nobles to fulfill their long dream to "help the king to rule thanks to their advise" that once translated would give something like "noble republic with a king".
Third. The effects.
For me, it's likely that the kingdom would simply and purely "cancel" one part of the debt. It's why France did in 1797 by exemple. It would carry an huge reaction with the consequence of many individual bankruptcy among the loaners, their clientele, and even among the urban population (you had a lot of loaners that wanted to attract the bourgeois or even the workers by promiging them a return of their investments).
It's likely tough, that the royal houses would help the king by sharing money, and by buying new charges (the crown would be forced to sell them, for having money).
Fourth. The political effects.
It would be the accomplissment of the noble program : regain the power they lost since Louis XII and maybe more. It would be really threatening to the royal power.
It's why Louis XVI preferred to call the EG iOTL. Because between the certitude that nobles would take many parts of the royal power, and the possibility of the EG being more nice and respectful...The latter was less threatening.
That said, he didn't expected the EG being so coherant (he wanted them to have an inner opposition between nobles and Tiers Etat) and while "enlightened nobles" and TE united...He kind of flipped out.
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To resume, in order to have Louis XVI, that was relativly "englightened" and continuing the long policy of french monarchs to oppose any form of noble political power, you would need something more organized, more radical and more power hungry than bread riots.