I truly hate subscriptions and try to avoid them as much as possible.
That being said, I fully understand why you are taking this route - developing and supporting more than a few Add-ons is a nightmare and it is hard to almost impossible to earn money with that.
For me and probably for many (most?) small to medium sized forums the pricing is waay too expensive - we would have to pay like 10.000+ $/year (assuming 250 $/quarter/website) for the forums we are currently using some ThemeHouse Add-ons.
So we will most likely have to stick with the versions we have right now and look for alternatives in the future.
That's kinda sad, but it is like it is.
Good luck anyway