I know you are right about the effects of all the coaching changes, and it's a very good point to make. We all need to keep reminding ourselves of this.
However, I do want to add an extra comment to one thing you said.
Coaches get 15 days in the spring and then August practice. not enough time for them to get everything perfected.
This may not be a great analogy, but I'm going to use it anyway. A person gets a new job in Peru. He gets six months to learn Spanish before he has to move to Lima. Now, obviously, the learning is going to continue after he moves, and it will even accelerate, but he is not going to be able to do his job well early on. He's going to make mistakes.
If (and notice the "if") the passing game doesn't meet fans' expectations in the first few games, fans will come on here complaining about the ineptitude of the quarterbacks or the receivers or both. There won't be much tolerance among fans for the learning process taking longer.
My point in the original post is that players should not shoulder all the blame. Some of the blame, sure. It's not their fault that there is not more time to get everything perfected. It's not the coaches fault that there's not more time to get everything perfected. But it is the coaches' responsibility to put the players in the best position to succeed. And, using the analogy again, if you see the new employee is not grasping the finer nuances of Spanish, do you keep trying to get him to see them, or do you concentrate on getting him to speak the most basic phrases well?