I think the question of whether bows actually get better with age is an interesting one. I tend to think they don't really get "better" so much as they just, well, change. And, the good bows stick around (so to speak) while the rest go wherever it is that all the bad music gear goes to rot and die.
It seems to me like an old bow and a new one can both be good and even very similar in performance, yet the old one will still have a different "vibe" - it will feel and sound
older. Of course I haven't done any extensive blindfolded studies, but when I was "bow shopping" I did play a pretty fair number of bows, all in the "decent" and better range. Interesting to note that the bow I ultimately chose was old and clearly had seen a lot of use over the years (it belonged, at one point, to an institution of some sort); it was not as "fine" a bow as some of the newer choices I narrowed down to and perhaps didn't even have quite the technical performance - but, it had the
mojo that made it, like Ken said, disappear or become part of my arm/hand.
To me, in a bow or a bass either one, that "mojo" is the most important thing. It doesn't matter how great the bow performs or how sweet the bass sounds - the best
music is going to come from the one that
works!