I dunno, KAM. I would think that most standard insurance policies (auto, home) have a commission rate of 10% or so. Life and disability in year 1 are probably much higher with smaller renewal commissions.
So, if the 500K in gross revenue are total premium dollars, then on average 80 to 85% might go straight to the insurance companies, leaving Mr. Dennis with commissions of well under 100K. Subtract salaries, rent, etc. and profit is probably 0.
If 500% are his agency's COMMISSIONS then the story is much different.