Experts and Mentorship Platform

My idea is a platform where people can get help from experts. Like stackoverflow, but you actually can talk to experts. Like codementor.io, but you don't pay experts for time but a flat fee to the platform.
The service would cost a monthly or annually fee and would be comparable to a retainer contract with an expert with the difference that customers would have many experts and not only one.
The profit would be shared between experts depending on how much help they could provide and there would be testimonials and ratings which they could show outside