So, I've heard like 3 accounts of people taking out seconds on their houses. I don't think this is a widespread practice. Do you know how many trillions of dollars were loaned out during the real estate boom? Unless you have data to back up your claims that most of the money in crypto is leveraged on the back of all these lines of credit you quoted, I think that's dubious to say.

At any rate, the value of cryptocurrency market isn't a reflection of the amount of money that has been poured into it. The market cap is a product of the last price paid on any given exchange times the circulating supply of currency. So a $500B market cap might be the result of less than $50B worth of cash infusion, so long as the last person who bought in paid $13K for a Bitcoin.