However, there still seems to be something of a disconnect between having a side project and turning it into something that is moderately successful; in particular, the challenge of making enough money to sustain the project and perhaps even elevating it from the sidelines so that it becomes something not so on the side at all.
Let’s conclude by returning to the slightly problematic nature of money, because it’s the pivot on which your side project’s success can swing, regardless of whether you measure success by monetary gain. I would argue that success has nothing to do with profit — it’s about you being able to spend the time you want on the project. Unfortunately, that is almost always linked to money: money to pay yourself while you work on your dream idea; money to pay for more servers when your web app hits the big time; money to pay for efforts to get the word out there. The key, then, is to judge success on your own terms, and seek to generate as much money as you see fit, whether it’s purely to cover your running costs, or enough to buy a small country. There’s nothing wrong with profit, as long as you’re ethical about it. (Pro tip: if you’ve earned enough to buy a small country, you’ve probably been unethical along the way.)
The point at which individuals and companies fail — in the moral sense, for sure, but often in the competitive sense, too — is when money is the primary motivation. It should never be the primary motivation. If you’re not passionate enough about something to do it as an unprofitable side project, you shouldn’t be doing it all.
Earning money should be a by-product of doing what you love. And who doesn’t want to spend their life doing what they love?