It's my theory that he tends to get bored, or runs out of time. I love Seveneves, but the last part seems rushed. And cries out for a sequel. Diamond Age too, but less so. And I found its ending to be quite satisfying. Ditto for Anathem.
The Baroque Cycle trilogy is actually a counterexample, being an extended followup and backstory to Cryptonomicon. That's also one aspect of the Mongoliad trilogy. And even D.O.D.O., in a way. But I can't say how, without major spoilers.
The Baroque Cycle trilogy is actually a counterexample, being an extended followup and backstory to Cryptonomicon. That's also one aspect of the Mongoliad trilogy. And even D.O.D.O., in a way. But I can't say how, without major spoilers.