i don't know much about how bitkeeper works, but i don't think it uses secure-hash-based naming of any kind

i think these are some of the things that led up to the transition to decentralized source control:

1. linus torvalds didn't want to use cvs because the social process of the linux kernel already depended on being able to ship patches around willy-nilly, but did want some kind of version control system

2. larry mcvoy had worked on a decentralized source control system called teamware, at sun, before the very first version of linux https://www.krsaborio.net/linux-kernel/research/2002/0528.ht... so he proposed to build a decentralized version control system to solve linus's problem, initially called bitsccs https://lkml.org/lkml/1998/9/30/122 but later called bitkeeper

3. tom lord decided the way we were doing version control was wrong and bad and spent years annoying the hell out of everyone and building software to demonstrate that a much better way was possible, and finally he convinced a lot of people, who started building better versions of the kinda janky arch/tla

4. there had been a lot of work on merkle graphs over the years, mostly for cryptographic applications, but in particular in the late 90s for decentralized filesystems; things like pgp, freenet, mojonation, bittorrent, and tahoe-lafs were popularizing this remarkable fact of being able to assign decentralized, secure names to pieces of content as long as they didn't have to be human-readable (a trilemma tahoe's designer zooko would formalize as 'zooko's triangle' until satoshi nakamoto found a solution). it may or may not be relevant that merkle's foundational patent expired in 01996; i think it's maybe more relevant that napster took off hugely in 02000, and suddenly decentralized and peer-to-peer systems that didn't have a central naming authority became an extremely fashionable thing to work on

5. larry got pissed off at tridge for trying to make a bitkeeper-compatible system and revoked the bitkeeper license after 5 years of people using it for linux. linus tried a bunch of the new free-software decentralized version control systems, including monotone, but none of them were adequate, so he decided to make a really stupid, basic version control system that would work well enough, and that was git

6. some kids started github, and they did a really good job of building a new kind of forge, and that took a lot of the pain out of using git. also because of how they set up the namespace the barrier to starting a new project there was much lower than on sourceforge, because you could call the project, like, 'notes', and because it was inside the namespace of your username there was no implicit claim to be the one and only notes project for the world.

you could definitely argue that critical mass for the internet was the thing that triggered so much interest in decentralized systems. but then again, zooko and ian clarke had spent a decade already trying to figure out how to protect human rights on the internet, and so maybe they were going to build decentralized systems once they figured out how, regardless of how many or how few people they served. or maybe if larry hadn't revoked the license, linus wouldn't have written git, and without linus's superb quality of performance engineering, people would have kept using svn except in cases where they really needed decentralization, and maybe mercurial wouldn't have become decently performant without competition from git. or maybe without 9/11 the internet would have developed in a totally different direction. i don't really know what other paths history might have taken