[jaclaz]

Well, that is exactly what the "businesses" revolving around it are doing.

Offering in your words a "centralized service which handles the hard part of a business such as transactions, business models, and disputes" cutting a fee from the value of the transaction.

The point of disagreement between our opinions only revolves around that service(s) being the "hard part" of the business and about the actual amount of the fees involved for these services.

Anyway a line needs to be drawn between an actual "sharing car" approach, as an example we have here blablacar where someone already has to go from A to B and offers a ride to recover some costs and something like Uber and Lyft, here the driver is going from A to B only because the customer(s) needs to go from A to B.