Because its a passing fad. Just like all the celebs were driving the Prius a few years ago, so too will the Tesla trend pass. Back then you couldnt get your hand on Prius either.
Whats worse is that the latte sipping lemings dont see the hypocrisy of driving the Tesla while living in 5000 square foot mcmansions, air conditioned to the wazoo, lit up like a casino at night.
When people stop buying f150s and other pick ups simply cuz they want one. When families realize that you dont need an excursion or an escalade just because you popped out a kid or two, nor you need the latest iphone/gadget/tv shipped from China, will we see an improvement.
You can reduce your personnal vehicle co2 emissions to zero but if all your goods are manufactured overseas, trucked in by semis, you are polluting the earth. Just sit on the 401 for 10 min and You'll loose count of trucks passing you. Each burning enough diesel in one Toronto to Montreal trip as your average car will in two weeks.