Good for you.Don't know why it could be called a "sickness" unless the purchase of firearms cause an issue with the family finances. I know of fishermen who have spent many 10's of thousands in tackle, boats etc., Golfers that have spent far more than their incomes affords. Not to mention Hot rod lovers, Harley riders, etc. .
My youngest Son (near 50 yo) and I collect all types of handguns, Rifles, shotguns etc. Even have some black powder. When I have and still purchase firearms, it doesn't affect my finances. I own my home, cars, have zero recurrent bills, pay all credit card bills in full when due. I will be 80 in May and my retirement income exceeds our normal living expenses.
I have many firearms with really no real use, several Mosin's, SKS's, also WW1 and WW2 rifles as well as many modern firearms like Garands, M1 carbine, Ruger Mini, Colts, Winchesters, Remington, Browning, Kimber, Swiss, Swedish, Mauser's, AR's LR-308, AK-47, 50BMG, Savage, Mossberg's etc. .
I used to shoot every firearm I purchased shortly after purchase and inspection (and repair / cleaning / tuning), however since covid and other issues there are a few I haven't shot yet.
My firearms have really turned into a good investment although I have no interest in selling or trading any. They will all be passed on to my son's.
I agree with your analysis. I wouldn't call it a sickness unless you do it under some kind of compulsion, or it causes your finances to be stressed.
In our consumer culture there's a bunch of other stuff that can stress finances.
I've slowed down on my purchasing for now (mid 30s) because I just don't have the time to enjoy what I have and I don't really want to add more calibers to keep around with ammo. But I can easily see me getting back into it when I'm able to shoot more. Hopefully in 10 or so years I'll be able to slow down with my business.
I'd also add I'd much rather be spending disposable income on guns and hunting supplies than TV's or video games. I'm trying to fight that battle early with my sons. I'll buy them 2-3 firearms if that will get them off of the video game system that they've been asking for.