I disagree that Git's biggest flaw is its lack of scalability. Cases where git needs to scale tend to be isolated to companies that have the manpower to build a finely-tuned replacement (see: MS, Google).
Git's flaws are primarily in usability/UX. But I think for its purpose, functionality is far more important than a perfect UX. I'm perfectly happy knowing I might have to Google how to do something in Git as long as I can feel confident that Git will have the power to do whatever it is I'm trying to do. A competitor would need to do what git does as well as git does it, with a UX that is not just marginally better but categorically better, to unseat git. (Marginally better isn't strong enough to overcome incumbent use cases)
And for the record: I think git-lfs issues are primarily usability issues, and tech improvements. The tech enhancements will be solved if there's enough desire, and as I mentioned the usability problems are more annoyances than actual problems.