There is a good comment on this in Wikipedia that I agree with:

"In-car Internet is an increasingly popular feature in cars, and according to a study by market researcher Invensity, by the year 2013, every new car built in Europe will be equipped with Internet connection. However, some technology writers speculate that the feature will not be popular as customers simply use smartphones to connect to the Internet rather than pay extra for in-car Internet services."

This may work in Europe because they have much better cell coverage. 

If I ever got a new car I would not pay for another cellular data plan just so it can be connected.

Stuart