The move to Perforce was for technical reasons only. Perforce lets you rename and move files without loosing the history of the file, it remembers what merges have been made, so you don't as easily screw up by repeating or leaving out a merge, it commits atomically and it remembers what changes were committed together, so it's easier to undo a change that affects multiple files, and, probably the most important thing in daily life, "p4 sync", the analogous to "cvs update", usually only takes fractions of a second, compared to the minutes it can take with a heavily branched cvs tree.
The issue of perforce vs. cvs and the issue of anonymous access to the source code tree are not related. Tehcnically, it's not hard to get the soruce code from p4 and into cvs, so the tree can be accessed via anonymous read-only cvs access.
Ask Richard Buck about actually making that happen.
