What has never been "officially" discussed is what I see as by far the most plausible scenario--that Dan Curtis himself pulled the plug. The timing makes particular sense because they were gearing up to make movie #2 and I think DC simply did not want the bother of keeping the series going simultaneously once again.
Oh, I completely concur with the truthfulness of what you've stated in reply #14 for the reasons DS ended when it did (I've made similar posts myself ). I simply didn't want it to go unsaid that we can't always count on the DS cast/crew to always recall everything as it actually happened. Unfortunately, more than a few have proven more than once that they have faulty memories. :- But then, we might too if we were trying to recall everything in detail that happened to us 40 years ago. I can't even recall in detail everything that I did last month!
Certainly not to try to prompt any new conspiracy theories regarding DS' cancellation - and certainly not to cast aspersions on anyone - but unfortunately we can't always trust as fact what the DS cast/crew have said at the Fests or even in print. Just look at some of the remarks in the DS Files books, not to mention the PomPress books - and let's not even go into some of the things that have often been said on the Fest stage.
I don't think any one of the elements Charles listed can solely be attributed to saving Dark Shadows, or making it the "phenomenon" it has become today. I would argue that all these elements, along with several others not listed, played a significant role in the shows genesis as well as its timeless appeal. How about Sy Tomashoff's gorgeous sets? Or the alluring music Robert Cobert served up? There are so many facets that made/make this show the phenomenal entity is has become. I just can't limit it to only one.