I just hope that at some point the Kalmbach folks will decide to put up a subscription site with the actual articles up. I'd gladly pay to have access to their out-of-print back issues. Harper's magazine has one up for subscribers that's really impressive.
Personally, I hate keeping back issues of magazines around. I recently started going through my 20 year library of MRs and snipping the articles I want to keep. The rest is going in the green bin at the curb. Just in doing that, I've been amazed at how many articles from the last few years I still want around. It's not like save-rate of the early issues, but far more than I had expected.