It sounds like you're wanting the the side-project to take over and replace your day job. Which is fine, but different from what I've been picturing for myself. Nevertheless, with that being your target: suppose you've grown big enough to pay the bills. Does the business still need to scale?
I see that as a bit of a trap, because people pass on what (to me) seems to be fulfilling work that could support a modest lifestyle and make big-growth choices that either crash them out or saddle their business with debt its market can't sustain.
