I read a recent test comparing the Tesla to the Dodge Charger Hellcat. In a drag race, the Tesla edged out the Dodge by 0.1 seconds. This is the result of the Tesla's all wheel drive. At the end of the 1/4 mile, the Tesla was doing around 113 mph. However, the Dodge was doing 124 mph and would simply blow past the Tesla about 50 feet beyond the timing lights, coming on like a rocket. One thing to note though was that they overheated the Hellcat's tires doing dumb burnouts. With a set of 305 wide Nitto NT555R tires (street legal), the Hellcat could crack into the high 10s (as has the Challenger Hellcat).
The Tesla has a very limited top speed. The Dodge can do better than 204 mph. Now, add the Hellcat's much lower price (about half that of the Tesla) and the Dodge is an unbeatable value. What the Tesla also lacks is the awe inspiring sound created by the Dodge's blown Hemi.
Next point... They did three quarter mile runs in the Tesla, and realized that they had eaten up nearly 40% of the car's range. Sure, it had great range at normal highway speeds, but that shrinks quickly when you use full power, and the P85D already has much less range than the standard S. So, unless you can find a charging station....
Tesla fits a very limited nitch. They are remarkable cars, but they are expensive. Electric cars in general are not selling well. The initial cost and limited range coupled with low gasoline prices are resulting in tepid sales, down considerably when compared to a year ago. There will always be a market for the Tesla, but that market isn't growing at this time.
It's also not a genuine performance car. Why? Because it can't make full power for more than few minutes without the batteries overheating and defaulting the car to limp mode. Several attempts to do a hot lap around Nurburgring resulted in this occurring. This involved both the standard S and P85D on separate occasions.
https://www.youtube.com/watch?feature=player_embedded&v=RWQ-dnpplaA#t=9