on the other hand, there's a strong incentive for group-organizations, specially profit-driven and "the show MUST go on" kinds of organizations to never depend on a single (or a small sub-group) of people to keep things going; lest somebody important gets hit by the proverbial bus.

IMO, this is also part of the challenges that come with dealing in software (understood as some sort of novel "substance"); in great part we (as a culture/civilization) haven't figured out how to deal with software (and in general, with digital artifacts) in the best way.