I think the trick is ease of access. If members have to go through complicated login procedures, you do lose a lot of them. Ebsco is offering a new search interface (it costs) which allows users to find articles from a lot of your resources through a keyword search from your home page. Members are prompted for login after resources have been found. This is a step in the right direction for magazines that are bound up in databases.
At our library, we have a lot of in-house use of magazines, but we are going to be reducing the paper a little this year and introducing Zinio (product of Recorded Books), which allows the library's users to sign up to receive issues on the day of release on their device of choice. Hopefully we will have it up and running by January - I cannot attest to its success as yet. There is an annual cost for the service (based on population size) plus a reasonable cost per subscription. Magazine publishers are apparently prepared to go along with this model because they also make money on advertisements, which are delivered to our users just as they are in the paper magazine.