Tesla is a pretty expensive car, so when the buyers no longer got a discount on the purchase of an electric car less people could afford them.

The Electric cars aren't selling because only a few people can afford spending $110.000 car, more than a house in some parts of the country. Even when the subsidy was in place most of the buyers were relatively wealthy people.

You can question the Danish taxation of cars if you want, but what's killing Tesla and others is the high price. The best selling car in Denmark in 2016 was the Peugeot 208 at $20.000. If electric cars are to take of they need to hit the $20.000 - $40.000 price range.

Tesla is a luxury which sold well among the well of segment of the population, when they were given a discount on the taxes, by the government.