Interesting that a smallish magazine is moving away from native mobile back to web while not too long ago I saw that some large retail company discontinued their mobile web site and require use of their native app (flipkart I think).

I don't think expecting a new audience just because you have an app is reasonable. I'd be interested in seeing how many new users they generate with just the mobile web site - I suspect that ultra loyal existing readers may take the time to bookmark their site and come back, but would be very surprised if their overall usage doesn't decline.