I gave it some thought years ago, especially when thinking about handgun purchases. I already had decided on revolvers only, so I stuck with .357 in revolver purchases. I have no other pistol calibers. That runs in one of the lever guns as well, and the bullets can be used in the .358 rifle.
I already had a 30-30, and would never get rid of it. I have never wanted or felt the need for an AR, AK or variant. My 30-30 or .358 serves me fine.
Wife shoots a 20 gauge, I shoot a 12. Have several of each.
Wife and I both shoot .22's and .22wmr. Have rifles and pistols in both.
That's eight cartridges if you include .38 special as part of the mix. Maybe more than some, but I know a lot of folks that outdo my arsenal by a mile.
22wmr would be the only one I would shed, but since I've owned a wmr of one variety or another for 35 years, it's unlikely I'll drop it now, especially since I have a rather large supply of ammo in that caliber.
I'm more likely to add one or two more- a .300WSM and 9.3x62. Screw the doom and gloom thinking goin' around. I'm going on with my living.