I did expect them to talk because I read, and also listened in this video, that users are thrilled to talk with the founders of the product they use.

I can understand what you say about unhappy users, they are the hardest to establish a conversation with, in fact, I had yet no luck with them.

I also try to contact my most engaged and paying users, very little luck there.

So, either everyone is laying (very unlikely), or I'm doing something wrong.

Fair enough. That point they made sounded weird to me. I'd certainly not be thrilled to talk to the owner of any of the products I use. Although I'd like if the owner was involved when I'm trying to fix something.

I'm an engineer, so I can definitely think about products I use which I'd enjoy talking to the developers and designers. Sometimes they can be the owners too. But if they are more about getting a business running and started, I don't care about that stuff. So, I wouldn't personally want to talk. I suspect people who are interested in running a business would like that. So, maybe your users are not mainly from that segment of the population.