why has no lending market explored the idea of making the calculation of interest charged be dependent on the LTV of a loan the riskier a loan, the higher the interest the borrower pays afaik only protocol that has smth along these lines is Maker with ETH-A, ETH-B...

i guess an easy reasons is that this makes the code more complicated as with a single interest rate you can simply calculate interest * time to get how much lenders are earning but much more complex systems have been built for DEXs