I was an AlphaSights "expert" on cloud for a while, they paid me super well and the people asked good questions, I stopped doing it because It was mostly hedge fund managers I was talking with, but given how much they paid me, I can't imagine what their clients must have been paying.
I did a few calls with an expert network firm once upon a time when I was an analyst. My limited experience was that they were really looking for inside information rather than broader insights and a lot of product companies actually forbid engaging with them.
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.
Mine as after DigitalOcean went public, I was long gone from it, they mostly wanted to talk about where cloud is going (would managed hosting/ftp hosts go away, what do you think will happen to the front end, blah bah blah) - They paid me hourly well over an order of magnitude more than what you were paid, heh. :)
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 .