But, in such case, if I were lender/borrower, I would definitely try to have a discussion and would look for flexible amount (in case, I wouldn’t be able to repay this amount, since the loan amount was small).
Just imagine, you have borrowed 1 BTC when BTC price was $10k. You earn $500/week and planned to repay the loan within 20 weeks. But when BTC increases to $60k+, it's not anymore possible for you to repay the loan within 20 weeks, nor even within a few years. Just sharing possible reason of the default.
In anyway, this is not the first time OP experience their lenders defaults, so i guess their decisions will probably still the same.
You are right that who are investors for long time 1 BTC is 1 BTC but when the price is too up and borrower are unable to repay then there might have some discount to the borrower. I cant remember now but I gave discount 80% to one of my borrower.