World-wide the death rate is about 3-4%. So that would mean we need to reach about 5 million total infections for 150k deaths, here in the US. 5m total infections is like 1.5% of the population.
It's really not that unrealistic IMO. I hope it doesn't happen. I hope it stays much lower, but to call it crazy out of hand when it's his job to know this stuff is probably not a great stance.
He could be wrong, for sure. Death rates change over time, and it's entirely possible there are more cases than we know about (which would bring the overall mortality rate down), but but I don't think it's a crazy estimate. I've seen much, much higher estimates tbh