This is not true. I've been following this thread with interest because I too have a feeling something is going on - I'm just not sure what exactly yet. Actually, I am in the camp that thinks this could be something far more sinister than a simple '30 - 60 day waiting period'. A simple waiting period sandbox would do nothing in the long-run to deter successful churn-and-burn SEO'ers from applying their craft - IF that is the Google's goal.
Anyway, I purchased a domain just over a week ago, added 8 unique articles and ranked for a high commercial intent KW in just a few days. Was the 'competition' high? No, it's not... BUT that is what you were saying, right? ONLY high commercial intent KW's are being targeted regardless of competition. Anyway, the commercial intent is there for this KW, people are paying for Ads and I ranked in just days with a brand new domain.