> 1k$ surplus income per month on a 18k$ bill means you'd have to forfeit all surplus income for 18 months.

Sure, if you were intent on paying it off as quickly as possible. Most likely your payment plan would be less than that.

Ultimately if enough "what if something else happens?" happen, you file for bankruptcy.

There's no such thing as financial security for anyone when you deal in the world of what-ifs.