Shitty jobs are not must vulnerable, quite opposite in fact. Automating some 400K/year quant job at hedge fund makes morse sense than automatng MCjob that pays 40K/year. More to that, shitty jobs are hardest to automate (we are nowhere close to good janitor robot, for example).
Also, you can not outsource cleaning toilets or hairdessers, but you can software development or building trading models.