It's a design choice toward a self-driving world, where instantaneous road notifications are less important to a person in a car than they are today.
On the Model S, this includes two high-priced options:
1. Enhanced Autopilot ($5000) quadruples the number of cameras from 1 to 4 and adds 12 ultrasonic sonar sensors and additional computing power to crunch the data.
2. Full Self-Driving Capability ($3000) doubles the number of cameras from 4 to 8.
People sure are willing to reach with their rationalizations.
You might be right. But consider that, maybe, Tesla has to remove what they can because they now realize that making a $35k EV without losing piles of money is very, very, difficult.
I agree with this, but cost savings and forward thinking design aren't mutually exclusive. I think the constraints of the former make the latter even more evident. Most cars with only one screen provide a driver's display. So why did Tesla choose a center display instead? I think it's because in the world they see coming, the center screen will be more useful.
That world may be five years away, but Tesla claims the Model 3 you buy this year will be fully self-driving, so it stands to reason they'd design it with that future in mind.