Are the Kett dying out?

The Archon is going against the wishes of his superiors by going after Remnant tech instead of concentrating on exalting the races of Heleus. My point was that their Exaltation dogma was in itself leading to their demise. That's the whole Empire not just the local fleet.

I do wonder how they evolved in the first place though if they only increase via Exaltation.

It would make them a more interesting antagonist if the franchise ever takes Andromeda forward again.

I recently noticed that SAM actually hypothesises about this in the Codex.

Yeah, on this 5th full playthrough I've been trying to glean every little bit of information from the game that I might have previously overlooked. I'm sure I've read this entry before but it just didn't register fully until it was hypothesised here in more plain terms. It could have been one of those entries that get updates instead of being completely new entries so you have to look carefully through the entry if there is a notification.

The Wiki also contains these entries on Kett vassal races which further shows that they need constant expansion to continue existing leading to potential civil wars and vulnerability to races fighting back. Basically the Kett are screwed long-term.

Eealen
One of the kett vassal races, the eelaen are a race that have been exalted past viable population. They now have become nomads who document and share knowledge.

Sirinde
One of the kett vassal races, the sirinde, which possibly translates as "eat their dead with reverence", have genetically poisoned themselves to stop exaltation, now have become dependent on kett neuroscience to survive.