From a guy that was a teenager in the early 70s, I had a lot of fun with a few hot 4 door cars. When the kids came along, the 4 doors made life much easier, putting a car seat in the back seat of a 2 door car was a pain in the back, really.

But all that said, we usually had a 4 door for the wife, she usually transported the kids, and either a beater car or truck for me to get to work in, that would have been whatever I found for a great price and the best condition, and then there was the hot rod, The hot rods were 95% 2 door cars, or 2 door trucks. We currently have 3 vehicles, a 4 door the wife drives, even though the kids have been long moved away, and a 2 door truck, and a 2 door hot rod, which is a 2 passenger car.
This "trend" is nothing new, its just more noticeable, and more common these days. The simple fact that there were not many 2 door vehicles produced in this century means your going to see more and more 4 doors, better get used to it.