I agree--I get slower every year. As long as I can put one foot in front of the other, I'll keep going, although it's getting progressively more difficult.
I think we should start a slow and light club!
I find as I get older that actually slowing down is difficult. If I go at my usual pace from years past I tend to go for a short sprint then pause to rest and repeat in an endless cycle. If I actually slow down I can keep going for a longer stretch. It is the tortoise and the hare cycle. The problem is that I consciously start hiking at 1.5 MPH and as soon as I forget I revert to my old 2 MPH pace. The only solution is to go out and practice more. Seriously thought I find it difficult to actually slow down.