Anything gated by the founder's personal availability is what the VCs used to call (dismissively) a lifestyle business.
Because you need your business to be big enough to pay your bills, not just theoretically net positive.
I have made some designs that I thought of selling too. For something like that to work, you need thousands of customers over the time.
It's ok to spend an year or two of weekends working into something that can replace some of your main income. It's really not ok to do that for something that can't.
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.
> suppose you've grown big enough to pay the bills. Does the business still need to scale?
No, that's the acceptable size.
I'm still 3D printing, but now focused on problems like dog and kids toys where I can give away the results.
“ This 3D printing business started with the help of my dog, at the time a puppy, and his desire to see my neighbor’s puppy. We (the humans) began talking, and as we ran through a conversation about dogs, the topic came to his trading card business. He’d source cards all over the internet for his daily WhatNot auctions with thousands of followers. Impressive—not only a home business doing real volume, but a lens into a world I had no idea existed.
I eventually noticed he had a 3D printed card stand, and with a printer at home, I offered to make him one myself. “Great,” he said, “I can sell them.””
So a guy selling playing cards started selling the things you 3D printed?
Is that the business?
I'd argue that's a "business", there were sales, supplies, a bottom line, et cetera, it's just the front-end part of the business was in collaboration with someone else.
It was pretty random, but there's all sorts of other 3D printing businesses like this for D&D supplies, tool attachments, et cetera.