In Linus Torvalds' talk on git at google[0], he mentions that the reason why he did not choose SVN (one of the reasons why he saw no other way but to build GIT)

In Linus Torvalds' talk on git at google[0], he mentions that the reason why he did not choose SVN (one of the reasons why he saw no other way but to build GIT) was that SVNs mission statement read "To create a compelling replacement for CVS"... which Linus hated with a passion and thus could not see why he would even use "a compelling replacement" of. Having experienced the workflow they learned from using another DVCS (Bitkeeper) probably also influenced his decision at the time.