I believe this was raised earlier, but gas prices do make a difference.
I know when I ran the math on buying a Tesla last year, including the $12,500 tax credit I would get, gas savings was a significant part of the equation.
Tesla themselves, on their calculator on their web-site makes a big deal out of savings on gas to better put in perspective the higher monthly payment for a Tesla. It does matter.
The future of Tesla, at least in a very material manner, is based upon the mass market car expected to start rolling out in 2017. There will be more price sensitivity with that car than there is with the S, or will be with X (and there is price sensitivity on the margins with the S and X) and consumers will be looking at alternatives to an electric car.
This will not be an issue for years to come however. The E car (for everyone) will be in such short supply relative to demand, that it will take years until Tesla reaches the point where they are selling to more “pragmatic” buyers of cars and not to pent up demand for those truly excited about getting a Tesla.
Thus, yes, falling cost of gas is a negative impact on Tesla. However, I don’t see the falling price of gas having any impact on Tesla for many years to come. Not until Tesla starts selling to more pragmatic customers, and that point is still many years into the future.
A Tesla S is the finest car in the world without any reservation, and also an enormous value standing on its own in comparison to the substitutes. It has the power of a high end Ferrari, the size of a large SUV, the safety that exceeds a Volvo, the reliability that exceeds everything, customer service second to none, and all at less cost than the closest equivalent ICE car, say a Ferrari or a higher end Porsche, or a to of the line BMW 7 series. It is a value product that delights.
The price of gas will some day matter to Tesla, but that day is so far away that it is impossible to know what the price of gas will be, in say 2019, 2020, 2021, so it really is not relevant, except as to market perceptions, and said perceptions can sway dramatically within days.