In no cases can any contract overrule the law. However, you are correct that the law is not being enforced, because it is exceedingly difficult for an individual person to tackle a massive company like BMW. The point of Rossmann's video, if I understand it correctly, is that we shouldn't just keep letting them get away with it, and actually defend our rights.
Indeed. It’s the price of the car itself that makes it more difficult to challenge - which is why people often go for lower monetary compensation through the small claims track (which has a max claim value variable depending on country)