Sales pay scales are very bimodal. A handful of rock star people make incredible amounts of money, most just get by alright, and maybe a quarter drop out because they can't close enough. It can be very high pressure, and a significant factor in your own success is outside of your control (i.e. depends on your product/service actually being good).

In a more civilized world they'd have higher bases across the board and the commission/incentive structures would be less "winner-take-all" but they operate those divisions like running greyhounds around a track.