I think it's a race to see who can be more out of touch between the Stellaris devs and the Age of Dogfights WWII devs. The latter are 3 years behind schedule and their latest "update" was to announce 3 new Kickstarter campaigns while threatening lying implying that if they don't do well, we might not get all our pledged stuff.
When people called them out, they played the delicate genius victim card from Seinfeld. I got a PM urging me not to ask negative questions in public because it causes unnecessary stress and anxiety to the devs and other backers. I was then assured that my pledge would be delivered in "a reasonable time". When I pointed out that 3 years late didn't seem reasonable to me, they stopped responding.
Wow. Well they certainly have no shortage of gall, that's for sure.
Just skimming through the most recent updates in that Kickstarter campaign made me cringe. I didn't think it was possible, but I much concur with your assessment that they really are as clueless and out-of-touch as the people making the Stellaris boardgame. (You have my full sympathies.)

Yeesh.
I'm wondering if Academy didn't get stuck w/ some bad contract terms, too, that give too many outside people too much control over what they're able to finally develop and release.
they've been late before, but never this late
By "outside people", I'm guessing you most likely mean the folks at Paradox? It's certainly not out of the question. Much as I like them as a company overall, they've had their fair share of missteps & misdealings. A scenario where they engage in much executive meddling with the boardgame's design and/or manufacturing/publishing process -- thus resulting in numerous delays -- certainly isn't implausible.
On the other hand, given what the developers themselves have talked about in the various updates these past four years, I think it's much more likely that the main culprit is that they have been suffering recurring bouts of "redesign-itis" and/or feature creep. In fact, it's quite painfully obvious that this is, in fact, what has been happening this whole time.
While I grant it's entirely possible that all these redesigns and added features were prompted by Paradox (or other 3rd parties), I truly, seriously doubt it -- at the very least, I cannot make myself believe Paradox/3P has been behind the majority of it. Everything about these yahoos gives me the impression that they have a collective case of ADHD on cocaine; they simply cannot remain focused.
Ultimately, however, I don't know what the reasons are for the 3-year delay (so far), nor -- quite frankly -- do I give a damn. At this point, I'm so fed up with the entire situation, that I've honestly kind of run out of words to adequately express my frustration. I just want the goddamn game already; I don't think that's an unreasonable ask.