From his book “On Writing:”
“…good story ideas seem to come quite literally from nowhere, sailing at you right out of the empty sky: two previously unrelated ideas come together and make something new under the sun. Your job isn’t to find these ideas but to recognize them when they show up.”
Even though King is referring to story ideas, I believe this statement can be applied to all ideas.
Trying to dream up the next big thing is often a waste of effort. Inspiration is random so don’t worry about having good ideas, worry about executing on those ideas when you do get them.