The problem with these crypto projects is they can never bring in the sustainable value. So they can only go through stages of bubbles and not downturns but just straight out crashes.

I would argue that they can but with viable products that people need. Polycub Kingdoms is one of them.

I do agree with you that the market will have the final say when it comes to adoption but I don't see things being as extreme as you described them. DeFi can find a place in the crypto world but only if it introduces mechanisms that create a balance between inflows and outflows of money.

Right now it does seem unsustainable and I'm sure that 90% of DeFi projects will not survive a harsh bear market but I do see innovation happening. People aren't interested enough to find it so they end up investing in scams and ponzis, which is the fault of the people, not the fault of DeFi and the whole industry.