I think Subversion's scalability is a red herring. Subversion is good for decent-size projects with decent-quality developers, a common situation in The Enterprise, but that's not because it scales better than a distributed system. Subversion is older, and therefore has more tools built for it already. Consider: TortoiseSVN, RapidSVN, SVN plugins for Visual Studio and other IDEs, and the various commercial SVN GUIs, project management systems, etc.
Git, bzr and Hg have some crutchware in development, but it's not as straightforward and widespread as the stuff for Subversion. It'll get there, but right now they all require some initiative from the developer, confidence on the command line, and an occasional RTFM.
Git, bzr and Hg have some crutchware in development, but it's not as straightforward and widespread as the stuff for Subversion. It'll get there, but right now they all require some initiative from the developer, confidence on the command line, and an occasional RTFM.