You're absolutely right. If being an entrepreneur is creating a product for a need, being a good open source contributor isn't any different (only you're working strictly for the notoriety).

I would suggest to OP to try to find a job where he is encouraged to release things he builds for that product FOSS, so that even if he doesn't find success in the popularity of it, hell, at least it means a lot at his day job and he has some skrill to show for it.