i guess in a way my joy is more about the converse of
@Bill Wightman's joy on advancements in cycling.
i still own a few of my bikes from the 80's, and i have a few bikes older than that, and i have a parts bin stretching back into the 70's, and i still have some apparel from that era, including a three sets of shoes, several jerseys and some wool underlayers.
i enjoy the fact that so much has not really changed. we have seen a lot of refinement, and better materials, but the fundamentals are still what they are. when my son turned 10, i have him my 70's schwinn varsity and when he started wanting more off roadish stuff i pulled out my kuwahara trials bike from the 80's (ironically this bike has become a unicorn. mine is the only one i have ever seen in real life and there is almost nothing on them on the internet.) and there are others in the shop. all of my kids have learned modern bike mechanics on old bikes.
i was super lucky when i was in high school and college that i knew guys who were national level bicycle racers, so i was blessed with many of their castoffs. (in the late 1970's had an Exxon- Cool Gear Graftek, yes, i sold it, yes, that was stupid in retrospect, but they had issues and i needed money as i was headed to college.)
other than my shift to recumbents (which did exist in some forms back then i just didn't ride them) to me the greatest advancement area have been 1. the technological quality devoted to the clincher tire and 2. lighting (
@bladderhead )
in the future,
i think cyclist safety has some big advances still to come, as i think automobile avoidance safety is going to advance.
and i think drive train is a place where are still big things to come, not just epower but efficiency.