He didn't put 1.5M of his own cash into his own KS. That would be stupid as he'd lose a cut of his own cash. He used that to start his company himself and separate from KS, i.e., hire people and get the basic facts and website completed before asking people for money.
In other words, he was invested, had a complete build document, good team balance, and his niche figured out before he created the kickstarter. This is my biggest complaint from this KS. It seems Brad and gamer insiders don't want to actually pay for anything out of their own pockets. Why should I donate to a startup, if the guys who'll reap the rewards won't even contribute to their own game?