To summarize:
1) Build something people really need, not a nice-to-have
2) Keeping customers is more important than just acquiring them
3) If you're not keeping your customers that means they don't want or need what you have
4) Changing people's behavior is really hard. Unless you have a significant amount of marketing budget, don't try to change people
5) "Distribution" is key. I have a hard time with the word "distribution" when often people mean "marketing" or "promotion" or "channels". That's what is usually meant. If you can't get an audience with the people you are trying to sell to, you might as well be invisible. I still don't get why people use the awkward term distribution for this.
6) You have to be better than what's already out there. If you're just as good, or worse, than the alternatives, then it's going to be really hard to make a sale. Alternatives don't mean direct competition. Anything that is an alternative for a customer to buy or use your product is real competition. This is especially the case if you're requiring the customer to change their habits to switch to your offering. You have to be MUCH better than the status quo and alternatives to do that.
7) Know who your customer is. Your user might not be your customer. Your customer might not have the itch to scratch even if the user does.
A lot of these are pretty common reasons for business failure but I suppose everyone has to go through their own personal challenges to internalize them.