I think it really depends. If electric cars suddenly get bought in mass quantities, that means something changed (like the sticker price) enough to allow that to happen. At that point, gas might not remain as attractive an option, as gas stations might start disappearing. (They need a lot of daily sales to make a profit since they sell based on volume. They might make more money converting into high speed charging stations.)
If for some reason people started to run out and buy electric cars all of the sudden, the price of gas would fall even lower which would push people towards gas engines anyway.. Tesla can't even turn a profit with them.