I feel like BDFLs are akin to the concept of village elders; they're not immune to corruption or scandal, but they often have this beloved status that can paper over a lot of cracks. That's probably dependant on their leadership style - the hard headed (Linus, DHH) vs the grandfatherly (Matz, Van Rossum).
Which, going back to your note on geopolitics, leads me to wonder: Is it just that more power corrupts more, or is it that (modern-day definitions of) democracy require a desire for power? I guess as the "FL" part of "BDFL" comes to bite more of the communities, we'll see better how different succession styles have different effects. I also wonder if the analytical nature of the individuals within the "populations", and inability to police defectors will mean uprisings will be more successful, either in causing BDFL attitude adjustments, or just overturning the community completely (for example, there's already a lot of momentum for a complete fork of Rails)
(Edit: having submitted this, I now see others have had very similar thoughts! Definitely an excellent conversation topic)