Apple entering the car business
You've got an Apple product on your desk, and you've got another in your pocket. You might even have one on your wrist. But is the next step something for your garage?Many outlets are reporting that Apple has recently indulged in a spate of poaching, picking up battery and automotive engineers from leading car makers and battery suppliers in the EV industry. That leads to more than just casual speculation that Apple is working on an automotive product of some sort. Will your next car be an Apple product? At the moment we don't know much, but it is beginning to seem at least a little bit likely.
There is zero evidence to your claim that Apple ordered the panel from LG. If they did I am sure that they would not allow any other company to get access to "their premium panels", and especially not to let anybody beat them to the game and release a 5K monitor before them, like Dell did.
And why do you think that 5120x2880 is a weird resolution? The numbers are higher than everything else around but they are just a multiple of very commonly used 720p resolution (1280x720 -> 2560x1440 -> 5120x2880 - doubling x and y at each step).
And I think that your argument that Apple loves "2x pixel ratio" does not make sense in this case. We are not talking about a phone or a tablet where doubling a display makes sense because the apps are full-screen and they scale easier. This is iMac where the applications are designed to run at any size you want them to be. And even iPhone resolution did not follow 2x (x and y) resolution jumps, actually the only 2x (x and y) change was from iPhone 3 to 4. After that the increments were much smaller and also aspect ratio changed.
And finally your comparison of who sold how many is irrelevant to the question. And you are also comparing apples and oranges (monitors and computers).