I think they should call it off, and announce that they will go back to the drawing board. Then restart talks with the API users and third party app developers.
What if they reduced the price of Reddit premium to $3/month and made API and third party apps only available for Reddit premium subscribers?
- Reddit would get many more premium subscribers
- App developers would be able to avoid managing subscription fee’s themselves and continue as before
- Users of the official Reddit app would not be affected
- Users of third party apps would have to pay for Reddit Premium - but maybe at a discount