The Government is not going to pay it forever. Its for early adopters and the Ontario Rebate is done after 2020. Thats the time we can expect a few models to match the price of ICE cars. 

A paragraph fro the Economist 

The falling cost of batteries will make the cost of owning and running an EV the same as that of a traditionally powered car in Europe by the early 2020s, even without the hefty government subsidies that many rich countries use to sweeten the deal. Better batteries should also conquer “range anxiety”—most pure EVs now run out of juice after around 100 miles (161km). If battery costs continue to tumble and performance improves at the current rate, the price of a car with a range of 300 miles could hit $30,000 by the early 2020s, according to Exane BNP Paribas. Slicker technology will also mean charging in minutes, not hours.