Living in the Netherlands, the price of a Tesla is around 100.000 euros. However, if I can lease the thing, the actual cost (due to tax benefit, etc) drops like a rock to a level that compares to a small, cheap car. For full electric cars you hardly pay taxes because the government wants to stimulate this clean way of transportation.
Now comparing to a Mercedes with a similar price is wrong, simply because the Mercedes with a similar price is costing much, much more in day to day operation: more tax (heavy car = high tax), no green car, so more taxes).
I believe that at least for the Netherlands, most hybrid or full-electric cars are driven by people that have a company car. We just love tax refunds. We hate the hassle of charging, so many hybrid cars in 2015 (Mitsubishi Outlander is a good example) were driven on petrol - not electricity.