I know someone who would be really interested in working on projects, enjoys programming, and so on, be very reluctant to take up projects that seem "iffy" with regards to financial success.
My point: being ruined financially by a project is one thing. It's another to program for fun. You can spin up a project for fun, as long as it isn't wrecking your bank account, and not have to worry if it's going to succeed.
I think it's a definition of "financial ruin." If you quit your job and blow through your safety net (not your retirement or anything) I don't consider that ruin.
> Ideally you want to see some traction and then ditch the job, doing so before would add additional stress due to lack of income.
I think this is the way that a lot of successful projects have come. If the idea is too big to solve in your spare time, it does not fit into this model.