Fishkeeping has always been a niche hobby, but let's break it down.
First most people who keep fish, lets call them casuals, typically start out with 10 or 20 gal tanks, betta bowls, and the rare occasion will have a 55 gal. I'd say anyone with a 75 or larger is a bit more dedicated. These people will overstock their tank with fish that shouldn't even be kept in these tank sizes. After a couple months of overfeeding and leaving the lights on their tank goes green, all their fish die and they are done with it, forever. They think it's some kind of magic to keep a tank alive. These people all will say that keeping a tank takes way too much effort.
Second, the hobby has died off a lot. For 1 the US unemployment rate went up and we dipped into a mini recession. There are only a fraction of LFS now compared to the 80's and 90's. Part of that is also to blame on internet business. When times get hard, hobbies, luxuries and novelties go first. So fishkeeping went bye bye. Most casuals either don't know you can order fish online, or they can't stomach the cost of shipping.
We are a rarity here, most people don't have a 75 or 180 gal tank let alone hundreds of gallons filled with rare fish. I don't really know if there is a fix. I understand this hobby has a steep learning curve. It's not like keeping hampsters, cats and dogs where all you really have to do is feed them. If your fish gets sick you can't take it to a vet, give it a shot, and take it home all healthy. All we can hope to do is reach out to our kids and young ones, educate them and get them hooked at a young age. Like I said in an earlier post I stepped otu of the hobby when my son was born. 2 years later I set it back up, took him fish shopping and found things he was interested in. Now we sit together for at least an hour a day in front of the tank watching it. My dad got me hooked at a very young age, and I hope I can pass this very special hobby on to him.