Keeping track of the major on line suppressor companies shows consistently low inventory.
Looking at 9 mm cans--low or out of stock for several dedicated 9 mm cans. Silencer Shop, Capital Armory, E Silencers, Quiet Riot. Seems that only "new" 9 mm cans are in stock==DeadAir Odessa 9. Gone are the Tirant 9, Rugged Obsideon 9.
Has modular multi caliber replaced the dedicated can? My observation of the Suppressor market..

It seems to happen every summer. It's a good time to buy cans. Many folks shoot less in the summer. Family responsibility, what have you. This allows one to purchase and sock it way a couple of perceived months early for the form 4 wait time.

Folks are also wanting the deals that happened last summer. Free can, 1/2 off can, free stamp. There is some of that going on, but not quite like previous years.

I also see quite a bit of technology jump in manufacturing processes. There are several 3d printed cans, and 3d printing has some interesting designs for baffle stacks. That may be a big reason why some of the older designs are slowly dieing off.

It seems more & more companies are going the Modular route. That and interchangeable end caps... people are just going .45 vs. 9 to get the job done.