I posted this in history subreddit and it was recommend to crosspost here since there was a lot of idle specualtive answers.
Basically, the Spanish Monarchy went bankrupt at least 6 times to my knowledge from crusades against Islam and Protestants, trying to hold the american colonies, and the Spanish Netherlands Revolts by the Dutch. Through all this there was never a revolution.
What actually happened when the Spanish crown went bankrupt? Did the king just say oh well, im not paying all you guys, and there is nothing you can do about it? Was he forced to sell land/title? How did he resolive it without the people/bankers/debtors rising up?
In medieval times it was often due to the expense of gear/weapons and training, hence a knight could put down a few peaseents with pitchforks due to better gear and training. However, gunpowder had been around for a while by now, so the ability for a common man to kill a "knight" or noble was there.
France on the other hand went bankrupt due to the crown lavish expense and helping US fight the british in the colonies. Yet this started the age of revolution and his downfall.
I'm really looking more for answers on why Spain didn't revolt, as opposed to why France did, which is where everyone mostly focused on the other thread.
I gave at least a partial answer about the nature of the debts of Phillip II here: https://www.reddit.com/r/AskHistorians/comments/chvgrg/how_did_banksbanking_families_in_the_early_modern/ev1683e?utm_source=share&utm_medium=web2x Basically, the defaults of the Spanish monarchy were never total, long-run defaults. They were short-run crises. Investors held the line against opportunistic default, the king started repaying again when he could, and the system continued as previous. The defaults did not cause a generalised breakdown of the Spanish state's capacity to spend, and creditors generally made money their money back fairly quickly.