A long-ish article about a talk that Michael Meeks gave about Libre Office, in which you find this gem (the emphasis is mine, not in the original):
OpenOffice.org has a somewhat checkered history when it comes to revision control. CVS was used for some years, resulting in a fair amount of pain; simply tagging a release would take about two hours to run. Still, they lived with CVS for some time until OpenOffice.org launched into a study to determine which alternative revision control system would be best to move to. The study came back recommending Git, but that wasn't what the managers wanted to hear, so they moved to Subversion instead - losing most of the project's history in the process. Later, a move to Mercurial was done, losing history again. The result is a code base littered with commented-out code; nobody ever felt confident actually deleting anything because they never knew if they would be able to get it back. Many code changes are essentially changelogged within the code itself as well. Now LibreOffice is using Git and a determined effort is being made to clean that stuff up.
This brings me back to my major beef with most "corporate" IT (even if the end product is open source): the people who have the knowledge don't have the power, and the people who have the power don't have the knowledge and won't listen.