No, I don't think everyone knows that. If we learned anything from the past few Apple product launches, it's that customers aren't shy about complaining even if they aren't completely sure what they're complaining about.
But this sales boost will confirm to Apple that it's ok for them to just release the same phone for 2 years with some spec upgrades in the 2nd year.
It is okay. The economics behind producing this many millions of a devices doesn't allow them to change the design every single year without jacking up the price. And for what?
A "tick tock" schedule, like the one Intel has adopted, makes tons of sense for Apple too. You just can't completely rethink a product design every year once it's matured.