Firstly, bug bounty hunting as a full-time job is just not a financially secure profession. It's a pay-for-performance system that requires you to produce tangible results in exchange for money. There is a large sense of security that comes with what you're accomplishing in other elements of life, as opposed to being continually held in opposition to one solitary variable.
I can tell you from personal experience that you can make thousands one month and barely scrape by the next due to variables beyond your control, like all of your submissions being flagged as duplicates, it's not always down to inability to find vulnerabilities. Of course, for the great majority of you, this isn't ideal since you most likely have responsibilities. I can only see this working if you have a significant financial safety net in place before making this commitment.