Monorepo + sparse-checkout looks a bit like a distributed subversion!
Most of my code (dating from before git was around) for various projects is in a single subversion tree and I check it out using git or mercurial to provide for local version control.
Features like sparse checkout are definitely welcome in git since the industry seems to have standardized on it.
In any case, with SVN you usually do not want to give write perms to everyone in all the tree, so you end up with effectively partitioned spaces, or you make several repos instead, or you put another layer on top. With Git, anyone can easily develop global commits.