Couple of comments:
We also subscribe to Cook's illustrated. Excellent 6x/year magazine with no ads whatsoever. Cook's illustrated also has a website, which they make you pay more for (which I hate - and haven't ever subscribed to the online version).
But, if the publishing of Zymurgy is so expensive, might it make sense to charge a basic fee wherein you would have access to the digital version of Zymurgy and for a nominal extra fee (which, when combined with the basic fee would be in the neighborhood of today's membership fee) to get the printed version? Seems sorta like charging extra for soft drinks, luggage, or even blankets on an airplane, but if there's some discount for a "digital only" model, then it may make sense.
I do realize that it costs a lot of money to print a magazine and determining how many fewer printed copies would be needed would be difficult. And it's probably not much cheaper to print 5000 copies vs 50000.
As someone mentioned, we all have access to an online index, but not the actual material. This is indeed a bummer for me personally since I lost a large portion of my issues from the 90's to water damage at home.
Just some lunchtime ramblings