There will be in v2. In v1 there's no point because the satellites don't have cross links, so they can only provide service while in range of a ground station, and there won't be any ground stations at the poles.
A satellite orbit has an inclination. If you launch it lined up with the equator then it will always stay over the equator. So you choose how far the satellite will wander north and south by adjusting the inclination at launch. The less the inclination the fewer satellites you need for coverage. So it is a tradeoff. Obviously the decision was made to only cover up to the place that population density falls off in the northern direction.
Added: Because the satellites spend more time at the northern and southern extremes they get denser coverage there. That is likely why they are initially offering coverage near the US/Canada border.
All the satellites in the first phase of Starlink are in 53 degree inclination orbits. This will give them coverage from about 60 degrees North down to 60 degrees South. In later phases they plan to have satellites in higher inclination orbits, but in the early stages, there just aren't enough people living that far North (sorry Scandinavia, you'll have to wait) for it to be worth spending 30% of the satellites' time over the poles when they can be over more populated parts of the planet instead.
