Since when has Apple ever really cared what other tech companies are doing?? Never.
That's what makes them who they are, they march to the beat of their own drum. They don't keep pace with anyone but themselves, which is something they should never change.
Apple most certainly cares about what other tech companies are doing. They would be fools if they didn't which they aren't. You do not think Apple is VERY aware of Samsung, Amazon, Google and others? They will absolutely keep pace with them however, there goal is to surpass them on every level (if they haven't already).
Understand, Apple is not the pioneer of all the products they offer. In some cases they enter the game later but again, with the goal of offering a better product.
So yes, while Apple does march to the beat of there own drummer (credit to Jobs), Apple clearly recognizes they need to keep pace with the industry/competition and also, outpace them to be the company of choice.
This is why I feel a bump in display size will be inevitable.