The thing you’re not getting is that Crabtree’s route is not a quick one. 10/10 times he wouldn’t be open when you say Joe looked at him, he just simply wasn’t given enough time. So you’re saying Crabtree was Joes read when Crab wasn’t even halfway through his route? Joe turned to Brown right when he got set after the rollout and waited for Brown to finish his break. Joe only looked to the right because that’s where he was rolling, not because those were his first reads.
The play was for Brown. It was designed so Joe could roll out and have a lot of time for Brown to run his route.
Yes, if Crabtree was not open when Joe looked at him, regardless of his route, Joe is going to move on. It is that simple. And Crabtree wasn't. Why? Because the Bills ran a zone coverage and the weakside linebacker sat on the underneath with a safety over the top. Joe likely read this and worked to his next read quickly. He could not afford to simply sit there and wait when the average time to throw in the NFL sits around 2 seconds.
You're never going to bank on your lone receiver to the opposite side of the field coming open in double coverage as your primary read. Again, that added an additional 15ish yards to the throw AND there was a corner and a safety on that side of the field.
Your first reads are always going to be to your strong side. If you're a right handed quarterback, you're first read will 99% of the time be on your right side. Why? Easiest throwing motion and easiest side to stop in a natural drop back. That's the quarterback position for you.
I'm also going to go off on a limb and just say that the rollouts were designed because the offensive line is still shaky and they wanted to get Flacco on the move and outside the pocket in a 2nd and 26 where the Bills could pin their ears back and just rush.
I don't really have any interest in debating this anymore, honestly. I'm glad you think you know exactly what Joe was thinking and that's totally fine, but I've said what I need to.