I wonder if that would even be sufficient. The sloped sides mean that even if the driver can sit directly next to the window, there's still a hard limit on how close he can get to whatever he is next to.
And the only time I see those tails unfurled is when it's an owner-operator driving at 55 (they know they're getting paid by the mile and so run as fuel efficient as they can).
A teardrop has a "relatively flat front end" just as every rounded shape has a point where its tangent plane is vertical, even a sphere, the "less flat" shape I can think of! It doesn't mean you can place a vertical windscreen in that point and still claim you're copying a teardrop's shape.
The "roll down window" thing is relatively easy to solve if they want to; you either make a seat that can slide to the side or redesign the front end.
I expect a redesign of the cab when the truck isn't selling every single one they can make.