Rich you have the true mind of an employee and you're comparing different business models. Besides, do you really believe that starting Turo was a zero risk venture for the founders? Of course not, they took an enormous risk. Way bigger than me buying a secondhand asset
and of course they should profit more greatly too.
Avon and Amway are renowned MLM schemes where you get paid commission to bring new 'reps' on board and you are then paid commission based on how much of the overarching firm's product you are able to sell. In these firms you are also incentivised to upsell through the commission structure.
On the other hand, Turo doesn't have any MLM commissions, nor are you required to sell their products, you chose what to sell and the fee structure is fixed at 25%. Turo are providing a marketplace for people to sell their own product, whilst providing insurance, customer support, sales and marketing services. Turo's model is exactly the same as AirBnB, eBay, Amazon FBA, UpWork etc, which have proven track records as being very successful business facilitation models.