I was a 90's saltwater keeper. I bought my first full setup used off eBay for $600 (pick-up). A 72 bow tank & stand, Marineland wet/dry with media trays and large bio-wheel, all live sand and rock. I still think a wet/dry is a great form of filtration and wish it was improved upon. In the 90's, the Mag Drive pumps were the best. I had 10K CFL mixed with blue actinic.
What were those first submersible titanium heaters in the 90's? They came in different colored packages for wattage but worked really good. The red one was the highest output. I miss those.
The equipment seemed to last much longer back then. I never had to replace a single piece of gear for the 3 years the tank was up and running before springing a leak.
Back then, LFS's used to carry a plethora of fish that should never be kept in most tanks, like the Panther Grouper (and most grouper species). Even my cute little Longhorn Cowfish, that was like a little sugar cube, would've grown far too large. Unfortunately, most predator fish that are cool looking also get quite big. They never seemed to tell you that part and the myth that the fish will grow to the size of the tank was in full affect.
I think nowadays we have focused a bit too much on new tech over what works. Nothing specifically, but some of the old school ways are still very much sound ways of doing things.