The total amount of these bounties are more or less meaningless. No one can make a living, 1st world wage with them - at least not consistently. All of the programs will pay you significantly less than what you'd get paid for an equivalent number of hours at a straight job.

What's more, most bugs will sell for 10x the bounty price on the black market.

Bug bounties aren't intended to be competitive compensation. They are intended to be tokens of appreciation given to people who would be reporting the bugs anyway. In this context, $500 vs. $1000 (a more typical reward from the chrome program) isn't too meaningful.

Whether this works for the researcher or not is up to them.