I really like their model as well. I think the really novel part of it is that, when you decide to stop paying the subscription, you keep the perpetual license for whatever was current a year ago. So if you just updated to the latest and greatest, and you love it, then you need to pay one more year subscription in order to "buy" it out right.

I think that's clever

Personally, if I thought I might have to downgrade a piece of software a year from now, I just wouldn't update in the first place, to avoid the pain of downgrading.

Even understanding that the goal is to incentivize continued payment, making users downgrade at the end feels excessively punitive IMO. Just let them keep the last version.

It used to be more friendly - you could have kept the last update before your time was up, not to roll back 1 year.

I don't think "keep using the old version" is a solution. We should accept the truth, which is that in today's computing world you can't "keep using the old version", because you will want the bug fixes, the security fixes, and you will need the software to be updated to newer OS versions.

Oh I agree that most users will want / should have the updates, but having the ability to still access an older version:

(1) means the lapsed subscriber can still access their data / functionality (at least for a while until OS compatibility issues kick in), and

(2) makes sure the developer is still actually 'earning' the subscription through updates, not just counting on data lock-in.

I agree. I completely avoid any locally installed software that's subscription only (e.g., Adobe Photoshop CC) because in most cases, I don't need the continual updates. I'm perfectly fine using a single purchase for years and just buying the update when the OS upgrade triggers it.

The price goes down over the first 3 years as well. Not sure why they do that exactly, but for a long time user like myself I'm happy they do!

I wonder if the App Store supports (or could support) this kind of model.

It does not support it on its own. You could build that functionality into an app as far as features go, but how easy they are to isolate will probably vary wildly, and it may be more work than it's worth.

It would mean only pushing updates to some users and not others, which would have to be supported by the App Store. Unless you jerry-rigged some way of separating your "updates" from the actual binary updates distributed by the app store, which, yes, would probably be more work than it's worth.