The reason we stuck with mtn for so long is that mtn checkouts are always resumable. You can get partial ones and pick up right where you left off. It was an incredibly important feature, and one that Git still does not implement for git clone. To do a successful checkout on the old crypto required checking out at --depth 1 and even then could take multiple attempts. Things are much better now, but it's still comparatively slow and inconvenient to check out a ~389mb repository over git than it was with mtn. But git is resumable once you have at least a shallow clone, and moreover git can produce a git bundle which is a file that works exactly like a git repository for the purposes of cloning. So what you do to turn the crisis(git non-resumability) into an opportunity(redundant copies of the whole damn repository history everywhere) is start is you start generating git bundles of i2p.i2p every once in a while, at regular intervals(I recommend the tenth of the month) and distributing them with bittorrent-over-I2P. That way, you can download a near-complete copy of the repository from many peers and spend a minute or two --unshallowing the result, rather than cloning to --depth 1 and repeatedly --unshallow until you have a complete repository.

There are actually even cooler things you can do if you apply some git-transport magic and a way of providing a single memorable alias to a series of infohashes, there are some systems that do this it's just a matter of porting their dependencies into the I2P network or replacing them.