Yeah, now you have kinda learned that...
In a world where almost any idea is getting built out so rapidly, you must have some glimpse that there's demand for what you're building before you commit to it, even if it's just one person showing interest
So many things get built and launched every day.
Some are useful, and some are not really needed but in the creator's head, they feel like something that's truly needed.
I have seen quite a few people abandon their projects on X/Twitter after months of building in public and putting in countless nights of work. Even when they eventually launch, the idea sounds good but it wasn't really in demand because there are already so many similar tools around serving the same purpose
I have seen quite a few projects go sideways that way.
I built two services for X a few months back and even before launch, I already had people interested in them and trying them out because I was testing everything in real time before launching.
During that process, I knew they would definitely be something that could sell well once I started offering them to a larger audience. I even made a few bucks from them back then.
Eventually, I stopped offering the services myself because I had too many other things I was working on at the time. If I decided to start offering that particular service again, I know there are people who were disappointed when I stopped and would likely love to continue, even though it has been months now since I last surfaced on X : D