Shows in general have got a LOT more expensive to attend, the vendor spends a huge amount of time and money doing them and all they see are a few tyre kickers having a day out at their expense.
Then HiFi has got it's own problems from two sides, the main side is the record companies who don't care about quality, in fact low quality hides lack of talent in a few cases too. The other side is the snake-oil hype coming back to bite them, for decades HiFi has been full of outrageous charlatans peddling expensive useless 'solutions' to non existent problems and in the good times of the 1970s-1990s this didn't matter too much, although it must have put a LOT of normal, rational people off the whole scene.
Then there's the population: We've now developed into a siege mentality where there's no room for quality in our disposable society, the money today is in cables - the easiest and most trivial part of the system, which is at the expense of everything else - even buying the music. Todays generation are no longer interested in HiFi - or even nice old cars, they skate past on a superficial, glittery media highway and the search for quality sound simply wouldn't occur to most of them, even if they could listen to some uncompressed unclipped music coming out of something bigger than an Amazon spy-box at some stage.
I notice the car audio scene does far far better, they have a bit of a 'Watts' obsession and the music is awful, but the fuses, cables and amps are all honest parts and it's quire refreshing in many ways. I can recommend getting some decent car audio speaker cable for HiFi BTW, it's excellent value for money and works a treat