I agree that execution is everything and an idea without a proper execution is worthless. So any smart ass MBA's with "game-changing ideas" but absolutely no idea about what it takes to actually build something from nothing need to take a long hard look at themselves and stop being bullshitters.
However, the title of the post is not 100% accurate as the term "stealth mode" does not specifically relate to not launching, protecting a non-existant "IP" or being unwilling to share your ideas.
Launching a product in "stealth mode" (as in avoiding significant public exposure and media coverage during the first stages of the product's life) can in some cases be a good marketing strategy and I can see why some entrepreneurs would choose to launch to a smaller group of customers and test their ideas and implementations before contacting Techcrunch, going onto Mixergy or wasting time meeting with VC's who want a piece of the action before anyone knows what the action is.