I’m genuinely confused why automakers (it’s not just Tesla but they seem to be the worst offenders) do this. Even if we get full self-driving cars tactile controls are still far superior for basic functionality to a touchscreen. For more specific operations sure, but I shouldn’t have to aim a finger mash to change the volume.
On Model S the right scroll wheel is used for climate adjustment, so perhaps in the future Tesla will make it configurable in user preferences.
All often used controls are contenders for the same constraints as well, since the more effort you have to put into locating and operating them the more time your attention is not on the road.
Sounds system volume can be essential in some circumstances, but is also used fairly often, so should be easily visible at all times (that is, you should not be able to hide it behind other panels unless it is very easy to return to the default display.
Climate controls are not essential, but also used very often, sometimes more often than sound system volume controls. They also should be visible in the default display.
A speedometer and fuel display are essential, and should always be visible.
I'm not sure how the Tesla display works, but if it allows you to cover these controls with anything and doesn't have a very simple and direct way to got back to a default display with these controls on it, I think that's not only bad design, but dangerous. Hopefully that's not the case.