Then actually taking the trouble to prototype it, show it to people, and find out if it has lasting value to any group of people you care about. And then you have to improve it to better fit those peoples' needs, and marketing it instead of taking a "okay, now come and get it" attitude.
Each of those steps is a huge obstacle which most people won't even attempt.
We see the finished product and think "who knew we needed that." But it's exceptionally rare to jump straight from a golden idea to a finished product. That's a marketing narrative after the fact.
Even "finding an idea" is fairly rare, and its going to waste a lot of your time if you expect it to be the first step to building a business. Find an audience, learn about them, figure out what their goals are and what choke points are keeping them from attaining them.
Then help them.