will quietly fix the issue at their factories, the ones who will notice the problem will eventually get a fixed model after many many returns and the ones who will put up with this or won't notice at all will be unsuspecting customers to Apple's 'bad' units that otherwise would have meant a loss for the company.
The returned units will be shipped back to factories and would have their LCD's replaced with the better ones and then injected back into the market at random.
An inquiry might be launched and a few QA managers will get the sack.
You won't know anything about this.