Yes I have noticed the Tesla on my A34/M4 trundle and they tend to all be sitting on 75 and not venturing into the quick traffic. I know different cars engender different driving styles quite often and wondered if that was what was happening?
Is that a "relax it is silent and calm" thing or a "range management" thing ?
I think it's an autopilot adaptive cruise control thing. I have found that the Tesla doesn't urge you to drive at 100mph, although it's very capable of doing so - it's similar, in some respects, when I had a Bentley. You tend to whisper along and not get hunched over the steering wheel trying to overtake everything!
The adaptive cruise control with cameras and radar is very easy to use and it is by far the easiest way of driving on a motorway. Find a car that's doing roughly the speed you want, press a button and the Tesla will match it's speed - you can quickly set the distance you want to follow too.
Reading about Tesla owners 'generally', many seem to become obsessed about much money they're saving per mile - even though the car is as cheap as chips to fill up with volts. So I guess some will drive at 60 to max out the range.