Having done both, cashier may be easier but startup and software engineer is not "insanely harder". It's somewhat harder, yes.

Working in the machines of the world gives you some understanding of why the world works the way it does. Ignorance gives you ideas for how it could. But the world tends to win. Let's see. There is no prediction of success or failure here, only that this is a concrete path to replacing lots of employment with... nothing really. We're already investing in curing cancer. Curing Zika or sleeping sickness isn't on anyone's radar and won't be because there's no money in it next year either.