You do need a market, not just a product. You also need to network to get input, partners, and build a BD pipeline. You don't necessarily need revenue at first, you need to prove external interest, whether that's a beta, pilot, or collaboration/partnership. All these things will add to your momentum.
I have plenty of worries about it - will the product sell at all, is the product too niche so I'll have sales but not enough to make it full time, am I barking up the wrong tree and there is already an open source free alternative that I've somehow missed, what if nobody likes it? All sorts of stuff, some warranted, and some just the usual fear of making something and putting it out there.
With that being said I do consider a big portion of success being luck, as any one lucky event could catapult you to riches, and any unlucky event could ruin any chance of that happening, but in the end you have to take a risk and put yourself out there for the lucky events to happen.
But as with all risky things you have to be prepared for it all to go to shit, and then have enough of a support network which will help you get back onto your feet.
I genuinely hope that other people have some more concrete advice here or even war stories to tell.
Solo, not one time in all of human history, has ever been the way to go.
Of all the lies you could chose to believe in life, this one is the worst.
You choose which engagements to take on based on your own capacity, and you’re not burning cycles on business development etc.
So advice like "use your network to find freelance / contracting" is not helpful to me. So there are two options for me: either find a way to make it work now, or accept the fact that I fucked up my life and I just need to wait for the inevitable replacement by AI. I doubt that every successful entrepreneur started to build a professional circle at the age of 21. But I might be wrong.
Yet, he is delighted to not have to run outsourcing shop anymore, and make same income with much smaller team and much more ethical line of business than outsourcing.