Startups that hire incorrectly fail. They don’t probably fail, or maybe fail. They just plain fail.
You must hire the right people. In particular, the early employees must be perfect. This is more important than anything else, including the product or business idea. Perfect teams can adapt to failing products or market/competitive issues and correct for that. That’s why great teams tend to work together over and over again, and sometimes start companies even before they know what the product will be.