I have been a part of these discussions and I can say that a big part of the reason is the extra height that the roll up door needs to allow proper room inside the cab. The door storing up above also removes room for a lot of other features There are some benefits to a roll up door, but it also becomes a maintenance issue with use and a typical door does not. CTL's especially vibrate a lot in movement and leaving the door up and running the machine is much different then an excavator roll up window which moves much slower with a lot more track on the ground to soak up the rough ground. A lot of guys are willing to accepted that with the ability to have a roll up door, but like most things there are no free rides. Deere used to have roll up doors and they went back to swinging doors. I have run the latest Taki machines with the roll up door and it seems robust, and they have had decades longer than anyone to get it right, but the cabs are really tall to allow for that. When you look at it cost is also a factor, roll up doors are more expensive and it takes a dedicated cab to allow for it. The small companies like Kubota and Taki are better able to utilize roll ups in their machines since they only have a handful of machines and there are all large frame machines. Someone like CAT, CASE, and BC which use the same cab over numerous machines of different sizes that becomes an issue. You lose the commonality of build that keeps prices down over the entire line of machines. They could certainly offer two cabs one with a roll up door and one with a swing door, but so far no one seems wanting to do that. It would likely make that roll up door option pretty expensive, and add more complexity to the build process. However like most things like this, if enough people talk about it things tend to happen.