Because the other companies give you all the promised features and standard features from day one and not trickling in features that are standard 2-3 years later because the car came with only half of its supposedly standard features installed.
This is not a positive, this is a negative.
Sure, if you thought the 2016 already had the 2018 features, that's a fail.
However, buying a car in 2016 that will have the features available in 2018 instead of needing to buy the 2016 car for transportation, then selling it and buying the 2018 version is a win in my book.