Hell, bump it up to $2.50/yr for those 15 articles/yr, same price as a single physical edition. GP would probably still be ok with that, and that doesn't seem unreasonable.
I'm not sure what magazines you were buying in the 90s for $6-$8 each, but they were certainly on the high end and not representative of your average newspaper, which were on the order of 35-50¢ at the time. Full-color glossy mags cost a lot more to produce than a newspaper, so I'm sure that's part of it.