As far as why not Mercurial, Mercurial was announced on April 19th. Git was announced on April 9th, and was self-hosting on April 7th. There were benchmarks comparing git and Mercurial shortly after Mercurial was announced, and git was faster, although at least originally it used much more disk space (this was before git had implemented compression and pack support).
Comments
Has Linus ever said why he disregarded Darcs and the other OSS options (wasn't Mercurial already starting to get somewhere at that time?).
Here are Linus's comments about Darcs: http://markmail.org/message/vk3gf7ap5auxcxnb
As far as why not Mercurial, Mercurial was announced on April 19th. Git was announced on April 9th, and was self-hosting on April 7th. There were benchmarks comparing git and Mercurial shortly after Mercurial was announced, and git was faster, although at least originally it used much more disk space (this was before git had implemented compression and pack support).