Not all LFS closing, there’s not much of choice in my area, online stores don’t deliver live stock , petsmart doesn’t sell marine stuff.Things are booming. That's why all the LFS are closing up. That's why you have to have a large tank custom made now.
I think what's booming is the number of people keeping 2 clownfish and 3 corals in a tiny sterile tank. Also booming is the number of people that are running a home frag tank.
a lot of people started to buy small tanks because it’s more affordable they came as plug and play for 500-600$ don’t see too many people willing to spend 2000$++ only to get lights for 4-6 foot tanks. At the same time if you decided to go big you probably want custom tank anyway, with things like overflow and supply holes in locations you like not a cookie cutter.