Best of luck trying to scale git. Microsoft took 3 years and they didn't add Office and Windows to it. And they nearly rewrote their own version of git.
IPFS seems to work effectively for storing versions of files. The downside is, as I mentioned in another post, that it's not permanent. Someone has to pin it or it'll disappear. But it doesn't require anything as complicated to use today as trying to modify git to do something it wasn't meant for.
Privacy comes because if everyone has the internet in their local cache (lol), then external servers can't say what YOU are REALLY looking at.