Yes, the metaphor is imperfect. Perhaps you can imagine that the top of the mountain is in the clouds, so although the initial idea is to "go that way", you don't really know exactly where you are going until you've arrive.

I'm not sure what the point is of drawing any of these metaphors - a market is important because you want to make something useful, and execution is important because you want to beat your competition. If you don't have a market, you lose in the start, if you don't have proper execution, you lose to competition. So do both.

So ideas without execution are worthless. And good execution of a market-less idea is also worthless.