The magazine analogy is just wrong. Once your magazine is out of date, you can't put it on the shelf and go grab a newer copy at no cost, with the only drawback being that the new magazine politely asks you to pay for it every time you open it.
It's not unusual for developers to include a limited amount of updates when you buy a license, that's all this is. Imagine that the next version of C2 (30) is a major realease. Now, if Ashley and co can manage a new release once a month, that makes 24 updates over 2 years- easily more than one major version upgrade in a traditional model. If you wanted to buy a licence to own the software under a traditional model, you would stop receiving updates halfway through that process.
Oh, and gamemaker is �25, not $25, last time I checked.
EDIT: Seems that YYG practice a bit of regional pricing.$25 or �25 depending on your location.