There are plenty of people who would like to be drivers. Labor participation rate is well off its highs.
The issue that the drivers need to be supervised. The local "owner" is the one who provides the local supervision. I am viewing this as sort of like a fast food franchise. A dedicated person with his own money invested can do quite well, and Amazon would also benefit.
That is if you use all of Amazon's preferred providers; go another route and you likely wouldn't even see that margin. Additionally, Amazon REQUIRES that participants provide paid time off, benefits, etc.
I also don't see any allocation of funds for an office, secured parking for 40 vehicles, business licenses and fees, etc. Toss in unemployment contributions, a couple workman's comp cases, and I'd imagine clearing $2,000 a week after taxes would be a challenge for ‘owning’ a business with a hundred employees and a singular customer who really is under no obligation to continue to use you as they explore innovations.
(Oh, and for that $2k a week, you're expected to ooh-rah employees 7 days a week with morning and evening ‘team’ meetings. Figure about a $23 an hour ‘wage’ with everyone but you getting time off.)
That's a pretty hefty treadmill that Amazon expects ‘owners’ to pound on.
All in all, someone going into it with open eyes, risking just under $100k and willing to put in 84 hours a week, it's not the best return on the money, but it's a pretty solid one. In more expensive markets, you might even be able to keep your head just above poverty level.