What makes it unsustainable is Gov't intevention in capitalism, not capitalism itself.
True to an extent.
Back when all banks were local institutions that only used depositors’ money for local investment, living standards universally rose.
But now the global interconnectedness of the markets allow for profits to be made in far away places where externalities are only felt by the local stakeholders and not felt by the investors or shareholders. In this environment Government is the only entity powerful enough to regulate financial behavior since relying on moral judgement has proven ineffective. And unfortunately the regulation has been written by interest groups and congressional staff unqualified to provide substantial oversight.
Once again, I like capitalism but I love and crave competence the most.