The odds are that a QB drafted #1 overall is more likely to be good than bust. If Murray was primarily a runner than I would maybe agree on that front of comparing him to other "running QBs", but he is absolutely a pass first QB or at least he was at OU. Of the last 20 taken #1, 15 of them were pro-bowl QBs.
He is referring to the history of the NFL and his physical limitations statistically say he is Way more likely to be a bust. He’s using 50+ years of history with those measurable.