In a way, their decision makes sense and I see other companies following suit. If you do a little research, you will see that over the past several years, the sales of 4-door cars has drastically slipped and continues to do so at an increasing rate, The reason for this appears to be that those needing/wanting family vehicles are opting for the more versatile utility vehicles (CUVs, SUVs, extended cab trucks); the sales of which have been upward trending during the same period.
As far as 2-door cars, I think the market will remain relatively stabile for some time. My reason for believing this is the demography, in general, of the buyers of these vehicles. The primary buyers include high school and college students, those a little older who's kids have left the nest, young couples/people who don't have kids, those who have two or more vehicles and, last but not least, car enthusiasts (like many of us).
What I see on a daily basis I think validates the above. In my neighborhood and those of family members in other states, as well as what I see during our many interstate road trips, 4-door vehicles are greatly out numbered by utility vehicles and 2-door vehicles. Since seeing this post, while driving through and walking our dogs on different routes through our neighborhood, which consists of just over 200 houses, I counted the number of 4-door vehicles I saw either parked or driving through. The total - 13; there was at least one if utility vehicle or 2-door parked in front of almost every home, even those few that had a 4-door. Additionally, out of the all the members of family (18 households/32 vehicles) only one owns a 4 door; one of my younger nieces picked up a ex police charger at an auction. Just my 0.2 on the topic