I also don't agree Model S/X are old. Model X is barely two years old. As to the Model S, I can't really imagine how you could improve much on its quite timeless exterior design. The interior doesn't need an overhaul either imo (I can imagine some "nice to have" things being added, like a ski trap/middle armrest for the back seats, some storage space in the doors (how difficult can that be) or even -tadaaa- a couple of free coat hooks
) but otherwise I think, as always, progress will be incremental and behind the scenes (faster UI, adding some more redundancy, higher definition screens, etc.). Is your two-year old MX so "old" that you would today buy something different? What exactly would you buy that is "less old"? A PowerPoint presentation?