I wonder where all the 123 wagon headrests ended up?

Before I ever owned a Mercedes I was convinced the wagons never had rear headrests, as I have never even seen a photo of a wagon with them, and I have heard a lot of people say the seats don't work with headrests

well anyways my wagon came with nice headrests in the back and I was pretty surprised. The funny thing is I don't even keep the headrests in the car because you actually can't fold the back seats down with the headrests in place. I feel like I'm doing something wrong because why would Mercedes design the best car in the world but forget about this pretty significant issue?