If it's too hard to gather any data, and it's too hard to do any sort of experimentation to determine if your theories are correct, it isn't time to just wildly theorize... it's time to pack it in and go do something else.
Your defense is too powerful. Fortunately, the dismal science isn't actually that dismal... or at least, it doesn't have to be....
Thing is, I am constantly working on concepts to develop a SaaS that could free me from a paid job. I actually do code and do pretty much everything (python (flask...), databases, sql, javascript, css, html, the whole package), because nobody dares to join a "non technical" guy, I have to learn it all.
But you know what's the most difficult thing? The business. Oh yeah. I can code an app from scratch, but I still have to convince people to use it. I still have to plan the financials (by the way, how do start up plans look like? Guess-working?). I still have to market it. I still have to make profits.
Which brings me to the point. I can't stand this bashing of business people 360 degrees. There are bad business people as there are bad developers. There is bad culture in start ups ("you non technical piece of ...") as there is in business. It's all a matter of degrees and looking around.
Your defense is too powerful. Fortunately, the dismal science isn't actually that dismal... or at least, it doesn't have to be....