Fewer people having to share in the profit. Now just imagine that scenario amplified many times over. The sales person makes a profit and the company makes a profit. The sales person then creates another selling situation with different customers. Each person, of course, is unique and has varied and special talents.
Most people can learn how to sell well.
Now you have the Power of Two, or Four, or Whatever. Every customer now has the opportunity to become a salesperson who develops customers who can become salespersons, and on and on. This geometric progression potential is similar to the old riddle about which is better, being paid one cent on the first day of the month and having that pay doubled every day for the month, or getting several thousand dollars paid to you one time at the end of the month. Most people think being paid several thousand dollars would be better. That is not realistic.