You are partially right. By far, the largest number of people who listen to music are doing it on low-mass systems, namely cell phones. They are connected to some kind of ear/headphones or, at home, to Bluetooth speakers or similar quality equipment. Nobody switched to those because of sound quality, except maybe you. They switched because of convenience. It has been that way for about 40 years.
Sophistication and advancement of technology made it possible that higher sound quality, whatever that is, is nowadays available from smaller format devices. Add to that the possibility to get content that was previously practically unobtainable. End-user experience is definitely simpler and richer, but technology used is far more complicated. Nothing wrong with that. Give it another 50-60 years and common devices will approach the sound quality of your Walkman in a package that will fit in your pocket.
I think Michael Green is right. Overall music listening is switching to smaller and easier-to-use devices but the driving force behind it is not sound quality. It is convenience made possible by advancements in technology. How room tuning and other approaches fit into that story about smaller and simpler is another topic. Kind of exactly the opposite, but not harmful at all. Thankfully, it is hard to take cover off an iPhone and continue using it as before.
All of that applies to major market, not very small marginal group that takes pleasure talking about fuses, cables, pieces of wood under the electronic components, and what not. They are in their little world that is less and less important to anyone, including show organizers.