Once the debt has been sold and resold a few times, I doubt collections companies have much incentive to actually sue for this amount of money, let alone an ability to actually win the case.

They don't need to sue, they can just list your debt with credit listing company and put a mark on your credit history. That can be annoying enough to settle a debt.

From personal experience neglecting debts I believed to be unjust, I've not gotten any dings on my credit rating inspired by collections companies who acquired the debt for the cable box that I never returned, after paying 3x its value in rental fees.

This didn't stop them from calling me and threatening my credit rating, but it seems their threats had no teeth. /anecdata