What a rather long post so I apologize if I missed something in my speed reading of your dissertation. I don't see road cycling as being on deaths door as much as it is certainly a locality issue for sure. I think too that price of cycles could be a deterrent too as the technology increases the price tag along with it does as well.
I read a article stating that road bikes are increasingly seeing the popularity in disc braking over rim brakes. Maybe, maybe not. I see disc brakes as a more complicated beast to maintain and certainly bleed off and in effect self-serviceable by many riders. I even wrench and build bikes up from the ground up and find them a pain to deal with. I love a nice rim brake but then again I am reminded that I am a dinosaur in this world or better yet, a spoke in a broken wheel of life!
So where does road cycling as a hobby/sport go********** Its about educating the new generation on the benefits and those who don't but are cagers to share the road. I have found in my observation cyclist are our own worst enemy by doing stupid stuff on the road that creates the animosity toward the culture. We have to obey all laws on the road like a cager…….but I am digressing now into a new world totally off topic and I apologize.
So to the state of road cycling.....I see it as doing fine for now.