As they say, there's nothing more frightful than ignorance in action.
Have you ever heard of two and three finger gestures? And pinch to zoom is not difficult at all, specially with small screens where finding a (+) and (-) can be hard to find.
But your fundamental mistake is to assume that:
1. There's only one person in the car - the driver - and/or the passenger is incapacitated;
2. The car is always moving. No stoplights or you don't commute much, do you? For some people pinch to zoom is becoming second nature, demanding less attention than fiddling with windshield wipers.
Maybe we should abolish the windshield wipers next? Yeah those with intermittent timers you can regulate, what a freak of nature...