I agree with Landyman, the advert is not just trying to sell a car, but also a lifestyle. If you’ve ever had a look at one of those BMW owners magazines (not sure how often they’re produced? Quarterly maybe?), you can see that it is definitely trying to sell you a lifestyle. Well, I think so anyway.
Also, I’d imagine adverts are expensive so companies wouldn’t want to spend money on a long advert that runs through all of the specs and stuff. Just enough to grab your interest and make you go and check it out on their website.
The thing I hate most is when they show something like a BMW 340i msport then plaster “from £249 a month” in massive writing next to it. £249 will get you one with a cassette player and wind down windows.