Nice collection. It's not impossible. Only a few are hard to come by.
Thats some collection of 40 magazines, yea its not impossible but will/would take time, dedication and some investment - for example there is a 2011 New Yorker Magazine on ebay currently for $1495 - not mine sadly!
It's the ones that you never see on ebay that will be hard to source. The New Yorker has been popping up less and less. And I have also not seen the 2011 Economist for sale publicly in about 2 years. Last private sale I'm aware of was in 4 figures.