I've talked about it at length here a while back, but just to reiterate: the man himself is driven enough that he's willing to course-correct his work sched when he realized that there was a danger of burnout. I guess it goes to show that he is pretty dedicated to the craft that he's willing to make sound compromises in order to keep on working, which is why I have faith that he's willing and has what it takes to finish this before moving on to the next.
(There's also the fact that he mentioned a while back that he already has all the story beats outlined so it's not as if he's making shit up as he goes like back when he was making OIAL where he only had a general idea but not much else to go on. Not to mention that it's easier to work on something if you have an idea where you're headed)
No worries, I dont think at all that the game will ever be abandoned. I just think that an already completed game should be valued higher than the plan of doing a new game. I have no doubts that Caribdis will finish Eternum. And I think that he has the story in his mind already and basically finished and just needs to do "everything" around it, is the reason for it.
And this is most likely also the reason he has this much passion and fun on his project. He does not cater to people who want something different (e.g. I have rarely seen people saying that models should change, which I see in other threads), so he never runs into the problem of working with things he dislikes. (Also, lets be real - money will also be a reason.)
Personally, I am very happy about Eternum, simply because of its existence. When I discovered OIALT, I was sceptical, but it turned out very good and I think back then Caribdis was underrated. But nowadays, you cannot get around Eternum, it is basically THE game currently.