just before SMB started dev i started to make a living (20-30k a year) off my sponsored flash games (though flash sponsorship’s are basicly dead now). so im sure i would have continued doing flash games for a few years till they petered out and in the mean time been working on something larger to sell on steam ( i already had an in when Gish went up shortly before smb came out).
but if that didnt work out id probably be still doing illustration freelance for tshirt design.. i did a ton of that back in the day. and maybe working at gamestop part time.. if it didnt work out at all id just get a job at a company that was local i guess.
id do whatever it took to continue making games and making a living :)