The rear suspension on the touring bikes is another area where a decision made for production by HD really escapes me.
Shocks of a type like the Progressives are undeniably better. They will also require less regular maintenance by the rider just because they won't leak down like the air shocks do. They're safer and more comfortable for the rider. There is less overall maintenance due to the lack of air lines and fittings. They would install on the assembly line faster (also due to the lack of air lines). But yet we've had the air shocks on the touring bikes for years; even on the front for a few years.
Can they be that much cheaper to manufacturre? And, even if there is a significant difference, how much cost is worth the difference in handling and the safety thereby accrued?
Now Now two lane rider....
The point you are making is valid and the shock by Showa that is used is significantly cheaper. Harley Davidson is so locked into the decxades old design of what they make that technology that will markedly improve your handling, braking or rideability of these bikes is your responsibility....not the MoCo's. Remember, this bike is just a platform. Sort of a do-it-yourself starter kit. The MoCo does not give two hoots about it because it sells. The most advanced platform offering that will get any play in that area is the V-Rod. That is where you would possibly see any area of significant technical offerings that are even in the same decade of technology that is accepted in the Harley circles of riders. Most of the H-D constituents are having a hard enough time accepting the hydroformed frame that the V-Rod has.
With regards to maintenance, I think that the MoCO and the dealers feel that it is a good thing that the shocks require maintenance, especially by them, for you, as a customer are looked as a revenue source each and every time you walk through the door. It's why it's so difficult to get a straight answer to a question. They can't charge for the answer unless they are currently selling something to you. And even then, the money does not guarantee a straight answer.