I reckon that you're mostly right, up to an order of magnitude. I'd poke at the details a little bit though. For desktop work I'd happily replace multiple screens with a 55" panel. 4k is not enough for that scenario, although 8k probably is, and I would guess that 16k would be redundant. For less detailed use, movies/games a 100" screen would be better, but the target resolution is basically the same.
No idea how it works for VR but there doesn't seem to be much point trying it until it gets better than the 4k 28" screen on my desk. At some point soon we have basically topped out for resolution because of the reasons that you state. Sound can improve - but again we are close to there. 160k mp3s only became low quality when I bought some decent quality headphones, but they don't seem to be that far off.