I am sorry to say, but I think his other game
Decked in Love pulls our devs focus from Nothing is Forever (it's a new project and as such more fun to work on). And while I love this game the new project isn't for me at all. Unfortunately being such a different game I am sure will not be positive for the current supporter base which in the long run probably will lend to even longer production cycles.
Though who knows, there's been no messages on Patreon since he decided to pause billing until the release of the 0.8 version (kudos for pausing billing I must say).
I can categorically state that this is not the case - MrSL spent a relatively small amount of time on the prototype of DeckedInLove, and even less for the second update release. At the time he described it as a way to let off steam because the complexity of NIF was getting to him.
In hindsight, it's probably possible to speculate that that was a sign of the beginnings of burnout. NIF has an enormous amount of dialogue and a lot of complexity in the code to handle all the consequences of the various player choices and love interests. It's a lot to hold in your head while you have to write a volume of dialogue that is equivalent to a novella, and then render 100s of images, all within a deadline of 6-8 months. I do know that NIF was not his primary "day job" - it was a side project while he actually was doing real-life work/study.
In the end, I guess it was too much.
However, we should remember that he has not publicly said that he is abandoning the project. The most recent info was "targeting the end of January" which is only 2 weeks ago. The more concerning thing is that we don't have any newer update on that status.
In the end there's nothing we can do about it except wait and see. He's not milking anyone, so there's no real damage except people's thwarted desire in knowing what comes next...
Edit: I also wondered if the game is autobiographical, and what has really happened is that MrSL has gone on the run after getting a little too involved with a redhead chess genius...