An idea is a starting point. If you were to have a race to success, having an idea would put you farther down the road than starting without one.

That being said, the idea is worthless if you don't actually start running. Building a team that can run much faster might eventually swamp any gains you get from having a good starting idea. That team might also discover a new path that leads to a new and much better goal, therefore leading you to choose to abandon your original idea.

A bad idea can ruin a good team by having them run in the wrong direction for too long.

You seem to believe that people don't value ideas enough and therefore are testing them. You will often get free ideas from people who can't or have no intention to run with them. This does nothing to prove they have no value, they simply have little value to that particular person.

I think the idea vs. execution argument is the hacker version of the nature/nurture question. For most things that matter, both contribute to varying degrees.