Related: Paul Graham: "Almost all founders learn brutal lessons during the first year, but some learn them much more quickly. Obviously those founders are more likely to succeed. So it could be a useful heuristic to ask, say 6 to 12 months in, "Have we learned our brutal lesson yet?"" "The most common lesson is that customers don't want what you're making. The next most common is that it isn't possible to make it, or…
It is an unnerving situation for founders, because the product might sell if you just added a critical feature, focused on a specific segment, changed the pricing model, etc. You could be one step away from success. Or you might not. It takes luck, pluck, and faith.
Related PG tweet: "When young founders build something that they don't want themselves but that they believe some group of other people want, 90% of the time they're building something no one wants."
And also related: https://mitchellh.com/writing/building-large-technical-proje...