That's a good idea, but I think at least part of the reason it's more complicated is that you have to design and fabricate a new face plate for the dashboard, and get a new set of controls every time you want to change something on it. Say you wanted to add a new button on a particular trim level only, because it has a feature that the other levels don't. You'd need to either redesign that whole part of the console for just that trim level, or else sell everyone at a lower trim level a console with an extra button that does nothing. Multiply that by N, for every tiny feature you want to sell on the higher trim levels. If you've got a digital display, of course, you can just go crazy and add all the UI elements (and features) you want.
> You'd need to either redesign that whole part of the console for just that trim level, or else sell everyone at a lower trim level a console with an extra button that does nothing.
Not necessarily. Sony has joysticks that can snap in and out of the advanced controllers. It wouldn't be hard at all to design a backing circuit board that supports this behind the trim. Switches aren't exactly delicate parts either so it's conceivable that a cheaper system could use auto shops to solder in a new switch into the board.
You could also have a simple multiplexed interface board near the head unit and the switches could use simple two wire connections back to that board. Or the head unit could just have this built into it. Or you could design and use a HID like protocol so different interface adapters with different capabilities could be plugged and unplugged from the system.
Is this worth the cost? Short term probably not but long term you might be able to make these accessories much more generic and so reusing them in newer designs might actually lead to good savings. Plus you'd spawn an active third party market for these parts.
I have a couple 15-20 year old base trim level cars and they use the exact same dashboards as their premium siblings. The unused button spots are still there they just haven’t been punched out yet
If you want the car to be fully customer configurable, you basically need a custom dashboard for every single car. You also need to think about what happens when the customer does an upgrade.