Most of the older people that had lots of tanks have either died or downgraded the number of aquariums so there's less work. Most younger people taking up fish keeping aren't in clubs and aren't really getting carried away like we did back in the day. When fish clubs were common here (80s, 90s, early 2000) there were lots of young people (age 20-30s) with fish rooms containing lots of tanks, and the old time fish keepers also had lots of tanks. But since clubs are almost non-existent now the number of people seeing fish rooms (and getting the idea of creating one) just doesn't appear to be there.
I guess the economy and covid really screwed things up too and made the price of fish keeping a lot more than it was back in my day. I was shocked looking at the prices of tanks, stands and lights today. I remember paying $20 for a 2ft tank, $60 for a 3ft and $80 for a 4ft tank. Plus I got my store discount which was cost price plus tax so half those prices
. I used to build my own stands and they were 1/4 the price of what the shop sold them for. These days 2ft tanks are over $100 and a 4ft tank is $300. Like holy moly that's expensive.
I had lots of tanks because I wanted lots of fish, and I got them
I also needed tanks to hold the different species of rainbowfishes I was keeping (60+ species, 80+ river systems). I needed tanks for breeding and rearing fry. I was collecting fish too and wanted tanks to hold those fish. I had marine, brackish and freshwater tanks. Then I would see something interesting on the wholesale list and had to have them (20 Acarichthys heckelii, 20 swordtail characins, 50 Botia lohachata, 10 Epiplaty dageti, etc).
It was painful moving all those tanks and fish but I had a van and a good friend, plus a couple of weeks to move everything. But if you want a fish room you really need to own your own home and that's not easy now. Hell, it's bad enough trying to find a rental property thanks to covid and with interest rates going up, I can't see many people setting up a fish room any time soon. At least not here.