Just to be clear, are you being intentionally dense?
It's by far the most common type of loan a private citizen is likely to need. I want to buy an asset, I take a loan and use the money to buy the asset, if I don't repay the loan the creditor takes the asset.
I don't need to have 1.5x the value of the assets in anything to get such a loan. I just need to convince the creditor that (a) I am likely to eventually repay the loan, and (b) that the resale value of the asset will be sufficient to cover the loan if I don't pay.
If DeFi loans can't handle this scenario, as far as 99% of the population is concerned they're not loans at all.