The application of DeFi as a lending/borrowing platform has some serious flaws and I doubt it could ever realize as a genuine debt market. The first problem is collateral type. Most of the DeFi lending platforms only accept collateral in ETH blockchain assets which are commonly ERC-20 tokens.
collateral-based lending is extremely limiting right now, but it's worth pointing out that in the future, asset tokenization could make defi significantly more useful.
let's assume that titles to real property, automobiles, boats, etc could be tokenized/digitized and precedent could be established where courts recognize these titles as legally binding. conceivably, this would enable defi platforms to extend services to the traditional mortgage and auto lending industries. this could be extended to anything where traditional certificate of titles are used today.
With the current model, DeFi will not able to integrate the 'tokenization of real assets' even if such on-blockchain asset is legally bound. Instead of working on P2P model, DeFi lending platform works on 'liquidity pool' model. Number of lenders together contribute to the pool which is then disbursed to the borrowers accordingly. Hence, there is no clear relationship between the buyer and the seller. It maybe possible that $40,000 I borrowed was contributed by 15 different lenders.
In such scenario, holding and liquidating asset would be impossible because custody of asset cannot be linked to a single individual.
So in short, DeFi model will only work if real value is on blockchain (like tokens) or value is backed by real value (assets created after staking tokens). In order to make tokenization of real assets possible, we will need a middleman who will first take custody of 'digital legally bound on-blockchain asset' on his ETH address. Then he will create another 'set of tokens' whose value will be equal to the value of digital asset less middleman's commission. Then these 'set of tokens' will be distributed to the lenders in ratio of their contribution to the particular loan.
Example: I am a borrower, I want to borrow $250,000 by giving my property having registry value of $320,000 as the collateral. I created smart contract and transferred the rights of my property to the contract address. 10 lenders contributed equally to my loan ($25,000 each) and transferred the amount to the pool' address. Then middleman created another smart contract. DeFi platform sent $250,000 from pool's address to the middleman's contract address. DeFi platform got back 10 TOKENS immediately on its pool address from the middleman's contract address which in turn was sent to each lender's ETH address. Middleman then transferred $250,000 from his contract to my contract address and immediately got my property's digital asset. Now my asset is locked on middleman's smart contract which could only be released once all 10 TOKENS are sent back to the contract address by the lenders.
This system could work out but still be labelled as 'centralized' because custody of property would still be in an individual's control (middleman) even if he won't be able to unlock it from his contract address without lender's permission.