When and idea comes to the surface, it is usually many heads that come up with similar ideas at the same time and it becomes a race to see who jumps on it and makes it first.
Joe, you nailed this on the nose.
My advice to anyone is if you think you have a great high concept idea, act on it, don't wait. Eventually someone else is going to come up with the same idea and beat you to it.
True story. I think I mentioned this before. I was thinking about writing a film based on a group of kids who get lost in the country and see some man walking through the woods with a bloody sheet, they investigate and in return the man terrorizes them. (That's all I had at the time.) Got the idea off an old Unsolved Mysteries episode. Never worked very hard on it. A year or so later, "Jeepers Creepers" came out. Not exactly the same, but similar enough where if I tried to write mine, I'd just get laughed at.
Then last night, my daughter comes running into the kitchen, saying "you're never going to believe this." I went into the living room and they had a preview for a new film out called "The Fog". It wasn't a year ago, I was working on a similar concept intitled The Fog. I got the idea while watching Stephen Kings "Storm of the Century". Again, I didn't spend too much time on it, and I'm sure it's much different then what I would of come up with, but the concept is the same.
You never know.
Scripter, if you have a great idea, go for it!
Steph