How successful can you be just being a copycat?

Process:

Comes up with an idea
Googles the idea and sees thousands of existing products
Executes the idea anyways

If there's no competition, then it probably means the idea is bad. But at what point is there too much competition that as an indie dev, I shouldn't enter?

Or maybe I didn't even come up with the idea. Just go through BoringCashCow and redo every idea on there and see what happens. Will I find success that way?