For the people on the bottom that physically work and produce nothing really changes. All that people really need is food and shelter and in the western world we can afford to eat a lot less. The people at the bottom already live paycheck to paycheck and they know how to do physical work and how to fix things themselves. The people that will be hurt are the infirm that our modern society supports which includes the elderly, chronically sick and cripples. Most of us will someday at some point join the infirm.
This is the scenario after a "worldwide bankruptcy" All the land with all the houses and apartments will still exist. All the farmland that produces all the food that overfeeds our country and the rest for the world will still exist. All the fertilizers, chemicals, and natural resources will still exist. At least two thirds of the people, working to produce and distribute the above, will continue doing what they already do. Many of the poorest people of today live in luxury compared to a hundred and two hundred years ago. What will change is the "rich" will be out on the street sort to speak with their bank accounts decimated. There will be a memorable backlash against lawyers, investment bankers, and politicians that support their rackets and games.
Medical patents will be vacated and health care will go back to being affordable. Doctors will be better protected legally and not need insurance like the do now but will be subject to more public records, reviews and audits. Medicine will go back to being affordable comparable to the 1960. There will be no million dollar procedures unless you have a million dollars. People will die at 85 instead of 90. Doctors pay checks will no longer be quite so big but they will no longer need to support the insurance industry and lawyers. They will become more respectable and esteemed members of society back when children wanted to grow up to be a doctor not because of the paycheck but rather to be a hero of society.
Higher education will become affordable again but no longer be government subsidized.