While not quite the same thing, credit card companies do something like this all the time. If you are wealthy, you can get a card with a lofty available balance

While not quite the same thing, credit card companies do something like this all the time. If you are wealthy, you can get a card with a lofty available balance at ~7% interest. If you are not wealthy, you can pay ~19.5% on a significantly lower available balance like everyone else. It's not free in this case. But the lenders are far kinder to the wealthy borrowers. Look at how many times lenders have simply dropped the collections on Donald Trump's loans. He's been very fortunate in that regard.