This does not surprise me. Git's original purpose of managing versions of a tree of text files (i.e. the source code of the Linux kernel) pervasively influences

This does not surprise me. Git's original purpose of managing versions of a tree of text files (i.e. the source code of the Linux kernel) pervasively influences it, and I wouldn't expect it to be any good for working with binary files or large files. If somebody comes up with something that matches Git's strengths and also handles binaries and biggies much, much better then they could definitely topple Git with it. It'd take time for the word to spread, the tools to mature and the hosting to appear, but I can definitely see it happening. I think most people know that Git isn't perfect, but it's also the case that coming up with anything better is an extremely difficult task. If it wasn't, someone would have already done it. It's not like people haven't been trying.