It’s amusing you call Git fast. It’s notoriously problematic for large repos such that virtually every BigTech company has made a custom rewrite at some point or another!
For everything I've ever done, git was practically instant (except network IO of course). It's one of the fastest and most reliable tools I know. If it isn't fast for you, chances are you are on a slow Windows filesysrem additionally impeded by a Virus scanner.
The mere fact that Git is unable to handle large binary files makes it an unusable tool for literally every project I have ever worked on in my entire career.
Takes 21 seconds on my work laptop, indeed a corporate Windows laptop with antivirus installed. Majority of that time is simply network I/O. The cloned repository is 276 MB large.
Actually checking the kernel out takes 90 seconds. This amounts to creating 99195 individual files, totaling 2 GB of data. Expect this to be ~10 times faster on a Linux file system.
So what's your problem?
If you’d like to argue that version control should be centralized, shallow, and sparse by default then I agree.
I get your sentiment, but I know how working with e.g. SVN feels. Just doing "svn log" was a pain when I had to do it. The "distributed" aspect of DVCS doesn't prevent you from keeping central what you need central. E.g. you can have github or your own hosting server that your team is exchanging through.
The main point of distributed is speed and self-sufficiency which is a huge plus. E.g. occasional network outages and general lack of bandwidth are still a thing in 2026 (and remain so to some extent for the foreseeable future).
Now, could git improve and allow some things to be staged/tiered/transparently cached better? Probably, and that's where some things like LFS come in. I don't have a large amount of experience in this field though, because what I work with is adequately served by the out-of-the-box git experience.