There’s nothing inherently wrong with mortgage-backed securities (they exist today!). In fact, there’s a lot right with them - they allow specialization by firms within the mortgage process and participation by investors with various risk profiles. It’s applying the Unix mindset of specialized composable functions to mortgages.
The 2008 crisis happened because MBSs became a bubble - investors stopped performing diligence (and risk models were crappy), so securitizers started packaging up crap, underwriting standards dropped, etc.
The 2008 crisis happened because MBSs became a bubble - investors stopped performing diligence (and risk models were crappy), so securitizers started packaging up crap, underwriting standards dropped, etc.