Vitality? Don't make me laugh. Audio as a hobby is dying, largely by its own hand. with the rise of digital music in the form of CD.
I fully agree with this part that audio as a hobby is dying. I believe the main reason is technological improvement, accessibility and habits of people and availability of other forms of entertainment.
With the availability of low cost Bluetooth/wireless/usb speakers, most simply can simply buy such speakers and connect to their phones/PC/tablet/laptops and listen to music. No doubt they do not measure that well, do not sound that well compared to better equipment. However, they are relatively affordable and perform decently (good enough).
Also the habits. People today want visual and interactive entertainment, eg. Gaming. My nephew feel that listening to music is boring. He tell me there is nothing to see, only listening to sound from 2 big ugly boxes and staring at the wall. There is no interaction at all. The phone is way more entertaining...haha
It's not just audio as a hobby, many other hobbies are dying too. I like building models. Sadly, few are keen in it today.