Sure, adding a flat inch to the trunk lid will increase efficiency, and adding 2" would increase it more, 3" even more.
Where does it end? Tesla had to pick a point at which they were comfortable stopping. So no, they aren't going to redesign their truck because they've already made the decision where to stop.
While drag coefficient is a part of their design focus, it's not the only thing they design for.
They're trying to mass produce a car, that will appeal to the masses.
They aren't making solar racers.
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I agree and support your point. In reality I question how much the stock spoiler on the 3 and Y actually helps. It's likely more so for visuals, which is fine as it does add a nice touch.
It's a challenge to balance style with aerodynamics. Although polarizing, I think HMG did a great job with the IONIQ 6 in creating a Sedan with such features with the aggressive rear slope to achieve one of the best drag co-efficiencies in the automotive space.
To HMG's credit, the've also created a boxy KIA EV9 true SUV that has very respectable drag co-efficiency numbers of just 0.28, which is better than an land rover.
Tesla as you've implied is all about:
Least amount of material as possible + Fastest Production + Removing things and market it as it being an upgrade/feature (Complete Apple iphone move) + Exciting the clueless fanboys + Most cost effective method + Screwing Tesla owners where they see fit best = Tesla.
There's no way Tesla is going to go out of their way to actually do something meaningful past the line of "just good enough." + "within spec." - To their credit the Model S Plaid is an outlier in that there's nothing that can touch it in straight line performance for $90K. For that I'm a big supporter of the S Plaid and will be replacing my 3P with it in the near future.
In some ways I think that the design of EVs are somewhat limited, in respect to achieving the best range and aerodynamics, to the current battery tech. It's not that the battery needs to get bigger, but once we get closer to solid state, the slice in the pie of having to design an EV with drag co-efficiency in mind will become slimmer. ie... all this adding an inch, to two inches to making a car look like a pebble for maximum aerodynamics will become less important.
With EVs we're limited by the battery tech at the moment. It's all about having a balance. Tesla and other EV makers could easily slap on a huge battery back, but that's just dead weight and not practical. - On the flip side, we're seeing this on the new Silverado that has a 200kWh battery, which is insane! Imagine a new battery tech that has the same amount of power in the same battery pack. - This is what makes EVs so exicting.
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