Your reasoning of good ideas and their implementations are wrong like most people.
If something is a good idea, it DOES NOT mean "everyone would be doing it".
You see, there is a thing called "barrier of entry" to ideas.
If someone has an idea for, say an app, there are a million things to do to proceed with that idea.
They need to learn how to
* design apps
* code apps
* market apps
Or if they want to hire people to do all that, they need to
* have experience hiring people
* have a lot of money, or a lot of experience getting funding (crowdfunding won't work if they have no experience)
* actually, forget this list - if you don't know anything you will die.
There are years of knowledge required to execute an idea, so you really limit yourself to only a handful of people who have the ability to, and thought of the same idea as you. And most of those people will probably not follow through either, so to execute an idea you really need to believe in it.
Now for your challenge, I would suggest you do something a little bit different. Instead of coming up with an idea and going the whole 9 yards with it, you can just leverage other peoples idea, and just make money marketing it. This is known as affiliate marketing.
There are networks (called CPA [Cost Per Action] Networks) where startups or companies plug in their various sales pages for things they offer, and you as an affiliate get people to complete those offers. The most common way to do this is buying ads to those offers.
By doing this, you eliminate all but the marketing work of running a startup. Marketing is almost always what determines if a startup fails or succeeds. You gain experience in marketing, and you can do a lot with the inventions you code.