Well, not likely an impossibility, just a big inconvenience. I think there are almost always ways to find an article in a back issue. So were back to a "conflict" between property rights and convenience.
I believe that AAABEST had it nailed when he said "It's because the other periodicals don't feel they're losing revenue and the intent of LAT and WP is to put FR out of business, not to recover lost revenue."
So there is no "conflict" between property rights and convenience, rather "property rights" are being used as a "convenience" to put FR out of business. All the evidence points to this fact.