Not necessarily tutors, but I run into the same issue in Product Management. I need to do customer research, but the process of finding people to speak with is time consuming and very much like sales. To have 10 conversations, I'll probably have reached out to at least 40-50 people. I have to build a "funnel" of people in order to maintain having a few conversations per week.
Note: I experience this problem at startups that don't have existing customer bases. With companies that have existing customer bases, finding people to validate ideas and get feedback is not arduous .
Super-well paid is a matter of perspective. As I recall it was about $500 for an hour call but it's not like I personally got all that and was pretty normal as a consulting rate.
People could put up basic profiles with their skills listed and you could purchase a time slot with them. It’d be relatively low commitment for both the experts and also the advice seekers.
Some technical problems might be verifying expertise but this could be handled with a sort of social proof like how LinkedIn allows users to vouch for certain skills. In fact you could probably facilitate account creation by pulling from the LinkedIn api.
But yeah, good luck if you build it!
I made some money on Codementor for a time and enjoyed it while I was between jobs, but wasn’t easy to balance that with FTE so I dropped it after a while.