VersionPress tried and failed to raise $30,000 last year, but it didn't stop them from moving forward. They've now released version 1.0 of VersionPress, which they still call a early access release with a long to-do list.
The plugin essentially logs every action in WordPress with features built in to roll them back — and it all ships as a plugin. In Borek Bernard's release post, he describes 1.0, “though it is technically a WordPress plugin, it is one of the most complex ones you can imagine.” In response, the top-voted Hacker News comment (where the story took off today) is a hilarious response to that quote, that, “This sends shivers down my spine.”
I don't disagree with the commenter. Built in version control to the WordPress dashboard, for both files and database, sounds like a terrifying task — especially for a greenfield product. However, time will tell whether VersionPress can accomplish their goal. It does seem, if it works, that it could be quite popular.