I agree with
@deanrobi - there are many factors that determine the actual range that you'll get, and these can vary from day to day.
From my experience, the most significant cause of range limitation is WiFi signals (2.4Ghz) in the immediate area. I tend to get the longest range in remote areas far from houses/buildings. The furthest I've flown is about 1400 metres, and on average I get about 400-500 metres.
Think of the 3000m limitation as under absolutely ideal lab-like conditions. It shouldn't be an expectation. It's also impossible to see the drone at that distance, which leaves you open to big issues if you have a GPS loss.
Karma will never fly as far as a Mavic Pro as the latter uses a proprietary RF protocol for communication, whereas Karma uses 2.4Ghz WiFi. It's probably the first thing GoPro will improve in the next iteration of Karma. The specs though are a bit silly, as no one in their right mind (or within the laws of many countries) flies a drone 7km from the controller. It's a bit like PPI specs on phone screens - there comes a point where any improvement is just pointless, and comparing specs is just a dick-waving exercise.