That was Experts Exchange model before StackOverflow ate their lunch primarily because it was free [1] as devs would rather answer questions for no money (i.e. to help people & build rep) than little money which would turn the motivation from the feel good act of helping people to whether it would be worth it to spend their time answering questions, which for most devs it wouldn't be.

[1] https://www.joelonsoftware.com/2018/04/06/the-stack-overflow...