I have no idea about how this business works but I'm curious, how is it even sustainable? What's preventing the "many borrowers simply don’t pay the money back" from becoming "no borrowers pay the money back" ? Their sense of responsibility/morality alone ? What's the penalty of not paying back ?
Like a former employee of mine, you get sued, then you get a judgement against you, and then they come to your workplace and garnish your wages. At that point the borrower either pays the bill through paycheck deductions or quits and goes to a new job. If the new job is on the books, then the process repeats itself. If the new job is cash-under-the-table, then the loan is never paid back.