> I suspect that's unlikely, even if there were advanced life there for 2 billion years.
Why do you think so? "Continuity" doesn't have to be having the same government or the same political structure, or even the same physical form (the article itself talks about uploads and nanomachines). It just means continuity of technological development. It doesn't have to mean steady progress either; our civilization hasn't had that, yet in ten millennia or so we have progressed from basic agriculture to space travel. For this planet, we're talking about two million millennia, or 200,000 times the time we've had. All the variables we've observed in our civilization's history become rounding error on that timescale.
A mass extinction event would mean there wouldn't be a civilization on the planet at all. That's certainly possible, but for this particular subthread I am taking as a premise that there is a civilization there.
Yes, I mean continuity of technological development. I suspect that the prior millennium’s dark ages are but a pale inkling of how far a civilization can collapse, especially given geological time scales. I also suspect that technological development can plateau for sociological reasons.
Even during the dark ages here on Earth, there was technological advancement. Also, the dark ages weren't worldwide. I would be skeptical of a plateau in technological development for any significant length of time for the same reason: even if one part of the planet was in one, the rest of it wouldn't be.
I suspect that's unlikely, even if there were advanced life there for 2 billion years.