Over the years, I've also had powerful ideas that could either make a huge impact or a financial success. Quite a few a short time later did make it big. Often the timing was close that the people who carried it through may have had the idea at the same time as me or possibly earlier. That doesn't even matter. The difference is that I didn't act on my convictions.

After a while, I come to realize that success isn't the inspirational idea, that's the precursor. It is the effort put into getting that idea as a product into the hands of the people that can use it. It's quite similar when someone with an idea wants to partner with some devs to implement it, but want most of the company, underestimating the development iterations and scaling needed. The same is also true if you already had the idea and the implementation, even with product-market-fit and need to get the word out and make sales.

You seem to have roughly two options: (1) feel that you were very close to success and failed, or (2) that you had an idea that could be successful with much action and effort. The feeling of failure comes from believing in being very very close to success. You have given no indication that you acted on the idea--the winning formula consists of the refined idea AND the implementation, iteration, sales and marketing. If you did do all those things and failed, you can feel good that you did the best you could and was outcompeted. If you didn't, the feeling of failure should only be focused toward inaction, which is regret. I have some of those but don't dwell on them and direct them at my own inaction rather than as something that happened to me. Maybe this is the way, let the feelings of failure become a regret and learn to move on, don't look back.