Hey all! Friendly neighborhood AgileBits Support personnel here.
This was previously true. However, we've not determined that for sure at this point. Users spoke, we listened. 1Password 4 is still a ways away and we'll determine whether it goes MAS exclusive sometime closer to release.
That said, nothing is ever set in stone with AgileBits. We do after all have Agile in our company name. :)
Our goal is to try to make our customers happy. We did make the MAS version cheaper upon introduction for users to make the transition a little easier. The pricing was roughly equivalent to what an upgrade would cost from our direct store.
We would also love to see a way to transition users to the App Store from our Direct Sales, but as you all know, Apple doesn't provide a mechanism for this.
We do always welcome users to comment and offer their comments and suggestions. This isn't the place to do that, but feel free to voice your opinions and suggestions (politely please, we are human after all) at our support site: http://support.agilebits.com
I'll do my best to follow up here, but due to a busy day here I may be a bit slow. Best to contact our support site directly where on duty support can assist you more quickly.
[1]: http://support.agilebits.com/discussions/1password-in-mac-ap...