“I assume it’s a bad idea because no one’s ever done it” is a common logical framework. Common, but wrong.
All of the great ideas in history hadn’t been done before someone first did them. And ideas require the right conditions to appear. In his book Where Ideas Come From, Steven Johnson describes the “adjacent possible.” This is the concept that ideas don’t arise until their time is right, because they’re adjacent to things that have already been done. Maybe your idea just wasn’t part of the adjacent possible till now.
I also like to think of ideas as needing the right person to bring them to the world. Specifically, ideas require multiple pieces of knowledge bumping into each other in the same head. It’s when this happens that a spark appears for a new idea. Maybe your idea needed your head, with your specific knowledge bumping around, to appear.
And, I’m well aware that my files are filled with half-stared ideas that I haven’t had time to finish yet. Maybe your idea might be one that other people have actually had – but haven’t been able to act on yet.
Don’t be quick to discredit your own ideas. There are lots of good reasons somebody else didn’t get there first.