When I read things like "it was teaching me to be an opportunist rather than a visionary" and "I thought that I could try to disrupt an industry" I can't help but think that there's more to this story than just an inability to stick to one's guns.

I empathize with the author, and I have no doubt that in retrospect he may have legitimate reason to question the quality of at least some of the advice he received from his investors, but at the same time, in my experience, most successful businesses aren't built by those trying to be visionaries and disrupt industries either.