Agreed. Due to this fact, I have been getting most of my recent purchases pre-owned. I can usually get 30% or more off for lightly used gear which helps with depreciation. I'm still new to guns so I'm in the accumulation stage. Should not need to downsize for some time. Also I try to limit how many new calibers I buy just to keep ammo costs in check. I reload, so that is a whole other continent of the gun world.
Knives I have been in for several years, so my collection has really plateaued. I have a very narrow spec of what I like to carry and can pinpoint which knives I would like and carry based on photos and specs now. That is after going through dozens of knives that look cool, but didn't make it into my pocket. Either too big, too fat, too wide, too small, materials I didn't care for, etc. It takes much time and money finding what you like in any given hobby, which really is half the fun. Trying new things and growing in knowledge and appreciation for the thing/activity.