You can only control your efforts, not the outcome. A writer writes, a singer sings, a creator creates.

So long as you’re actually putting businesses out into the universe you’re a full fledged entrepreneur.

I can’t tell you why you haven’t been as successful as you want to be. That kind of advice is all over the place. Perhaps the comments here are right: figure out what the customer wants first and make a minimal first product. Perhaps they’re wrong and you should incubate them for longer or perhaps some third thing (partner with someone else? It’s not bad to be the drummer in the Beatles).

But I think self-doubt is a natural part of creativity and maybe even a sign you’re on the right track.