> Most importantly, I can't relate to my target demographic at all
> I'm not a small business owner. I don't have any employees, I don't have any physical inventory.
> I think this was my biggest downfall. I had to pay for content because I didn't know what business owners with a physical inventory wanted to read about inventory management.
How is this not painfully obvious to any independent entrepreneur? If you don't have the resources to do customer surveys and advertisements, why don't you stick to something you actually know? Because, assuming you are a reasonable person, a problem you have is likely a problem that others have. The main advantage, in this case though, is that feature brainstorming and iteration is much quicker...sometimes the time intervals are as short as it takes for a thought to reach the other side of your brain. And even if you don't have a market right away...or ever...you may have built something that is useful enough to you to markedly improve your life. So, almost a win win.
I can't count the number of times when, while working at an incubator, I overheard developers building the next awesome photo-world-traveling-sharing app, and trying to come up with features they think photographers might need...it was always painful to listen to.