As was said here, the problem is the collateral, until now I didn't find any worthful collateral to start a lending money business. Altcoins lose price fast and if someone has funds in Altcoins, he can just convert it to BTC, so why would this one borrow money?
And physical items, what would be nice to have as collateral, is impossible as we live in very far away countries and the mail costs are expensive and I think nobody would want to do it just to borrow money. There are better ways to earn money online...
There are also people who are investing on altcoins and we all know that in some cases the longer you wait for the higher the chance of gaining more profits that's why its better to lend it instead of selling it as there are tumes when a certain price has a low chance of coming back . Lenders are always looking for a stable altcoins like dash or eth the price won't drop that fast .
The collateral should be transfer digitally and easy to sell to be valid .