Look at evergrande in China, almost if not bigger than the lehman brothers' crash but China self regulated it. Same with COVID and stimulus. Retail investors are now more powerful too.
A real estate development company defaulting on its debt means losses for investors, most of which have diversified portfolios and can absorb the loss. $300bn in debt is a lot, so I don’t want to discount how serious that is, but they’re not a bank.
Lehman Brothers, on the other hand, was deeply interconnected with the U.S. banking system and touched tens of thousands of businesses. The $600bn they owed were not to “investors” but to businesses, insurance companies and other counter parties that were not prepared to absorb the loss. The prospect of unwinding Lehman’s positions was beginning a catastrophic domino effect on the global financial system. They were quite literally “too big to fail.”
Evergrande is just a big company.
Or maybe it never breaks and we should just pull the lever a bunch today and buy our way out of all the worlds problems.
My opinion is, bubbles burst when people panic and people panic due to lack of communication. In the past, you wouldn't see places like /r/antiwork or /r/wallstreetbets grab wallstreet's attention for example. The rich keep getting richer but they are also now better informed so that they know just how much carrot to hang on the stick for the poor. inflation is normal, hence so are bubbles. Bubbles bursting means failure of the system to sustain itself.
I guess my point is maybe that we’re in a fragile system rather then a bubble. It’s self sustainable in the steady state (to your point) but if it breaks it’s going to completely collapse and we just have to hope that we never reach the point where it could break. It’s a Similar line of thinking to controlled burns to manage forest fire before they get uncontrollably big. But in the USA at least, the safety net isn’t there to allow for controlled burns in the economy.