For me, it's looking like it's going to settle into to a total of about 25-28 counting all firearms, airguns, and muzzleloaders, as the optimum balance going forward between actually shooting and enjoying them vs. enough diversity to keep it interesting (& yes, brag a bit).
Sure I've got a list of 40+ others I wouldn't mind playing with, and years ago I had a lot more, but collecting isn't my thing quite as much as shooting & hunting is (though, yes, there is some satisfaction from the collecting part of it). I may decide to pare down to a slightly smaller cabal, in the 22-25 range. If I stopped hunting completely, I would likely be happy with more like 12-14, or maybe even less.
The most dramatic shift for me in the last 15 years was the reduction of handguns....down to just 3 (though there are 2-3 more I want). Handguns just aren't as interesting - they're 80% tool and 20% art & aesthetics. Rifles & shotguns are more like 20% tool and 80% art & aesthetics.
Also reduced the muzzleloaders from 3 to 1, and reduced bows & crossbows from 6 to 3. Simplifying is good.
Another big shift was I stopped collecting milsurp rifles - love them, but more into the "every gun has a specific niche/purpose" theme now.
Another big shift was deciding that just one semi-auto fighting / militia rifle is plenty enough. The focus now is my beloved hunting, varmint, and multi-purpose (scout) turnbolts. That's what blows my skirt - uhhh, I mean kilt - up these days. Ammo cost is a lot less than spraying and praying with a semi-auto.