Yes and I would also imagine that the trade-offs between writing a proprietary object storage and reusing the battle-tested object storage that everyone else us

Yes and I would also imagine that the trade-offs between writing a proprietary object storage and reusing the battle-tested object storage that everyone else uses would have been considered as well. It seems like the sort of thing that would be an interesting open source research topic if you could build an object database for git that performs better than its packed in filesystem object store. But it's probably not something you want to do as a proprietary project with fewer eyeballs on its performance trade-offs and more engineering work every time git slightly changes its object storage behavior which would remain tuned for the filesystem object store because it was entirely unaware of your efforts.