Maybe the total "stuff" burden should be calculated as:
amount of stuff owned * amount you care about it
Owning a small number of things you fetishise seems not so different than having a pile of crap that you don't care about at all.
The "owning less stuff" movement seems to have a lot more traction where rents are high and space is constrained. It seems to me that people tend to produce moral justifications for what are simply practical constraints.