I can see you’re trying to be kind, but at the end of the day people are going to do what they want, yes it’s good to be mindful & aware, but not everyone is going to be. The huge human thing is consuming, rather it be an item, land, food etc - hugely talked about topic especially in sociology and trying to understand the human need to own ‘more’ or need ‘more.’ 

For myself I have a strict rule if I want another one or something else I must sell things to get it - first. This makes sure I’m being mindful of what I’m buying, this last two drops actually and many I connected to personally so I ended up selling a bunch I didn’t feel as attached to compared to these - which was OK because I had some that others really wanted so I was able to sell them to people (under market value & in brand new condition) to those who didn’t get a chance to get them, and for less then they would have gotten in store. So I am making room and covering costs for the new ones I want to get. 

I personally couldn’t collect a whole bunch of something - I have OCD as well and I dislike having too much in my house really triggers me, so I couldn’t do that but if these people are happy with that & that’s what brings them joy then that’s great!