Also, this prophecy didn't come true. If anything it was completely ass-backwards - it's about the quality of the 737 MAX sim, not the plane itself, and it looks like Boeing's engineers believed internally that Boeing shouldn't have pushed so hard to release it given that existing 737 pilots didn't need simulator training on the MAX and felt safer flying on the MAX with pilots trained on the NG than they did about flying with MAX-simulator trained pilots. You may recall that the general narrative is that the crashes were, in part, the result of Boeing's desire to avoid MAX-specific simulator training.