I got 'slowed down' at 32 - spinal cord damage, total quadriplegic for awhile. Took 9 years to play again, and I still can't finger pick with more than 2 fingers. Still, I can play fairly fast when I need to. Not uber fast but... who cares? As I've gotten older, speed (and the sheer number of notes that often accompanies it) have been less and less alluring, often even a turn off.
I play with much more feeling now, having lived and lost and regained. And feeling is where it's at for me. My technique will probably never match 80% or more of the people on this board - both due to lingering neuromuscular deficits, but also because I'm a lazy bastard. But I play music with far more emotional content than I did when I was younger, and that, to me, is part of getting older - the sheer excessive exuberance of youth tempered by (one hopes) wisdom and deeper emotions. Or, as Carl Jung would say: we live the first half of our lives hewing to the 'prince' archtype, the 2nd, moving into the 'king' archetype - magnaminity, patience, depth take over from sheer physicality and wide-eyed romanticism. Age has tempered my playing, like a fine wine that has less of a burst on first taste, but an amazingly complex and nuanced finish. I am happy for the change. Change is inevitable. We will all slow down, all lose dexterity to some extent. How we accept change, or rail against it, that is the difference between discontent and happiness. I saw Larry Coryell recently, and there were no massive lightning runs. Instead there were these amazingly complex and delicate arpeggios of artificial harmonics that were lush and incredibly inspiring.