I also adore the series. It's become my favorite sci-fi I've read in years. You're leaving out the time required to communicate. Yes, communication would requi

I also adore the series. It's become my favorite sci-fi I've read in years. You're leaving out the time required to communicate. Yes, communication would require less energy, but time is a constant that even type 3 civilizations could be in short supply of. The chain of suspicion calls this out explicitly, it's not that the civs cannot communicate, it's that due to the extreme lengths of time required for back-and-forth communications their societies are likely to significantly change during communications, leading to higher probability of the technological explosion. What medium was primed for the technological explosion on Earth since the industrial revolution? I mean, I reckon we could point to an array of things that have seemed as though they would be a limit, but thus-far we've always found ways past that (see: peak oil). I'm not trying to indicate I think our trends _will_ go on forever, just that it seems possible they could.