I have seen some data that makes me think you may be right. I haven't looked at database projects yet but looking at the code bases of other programming languages and big systems (such as Linux), I see the Rust file count going up. That being said, I did recently look at SQLite and that is still all C. It's on my todo list to look this up for all the major open source DBs.
I was thinking of giving AutoGPT a try to convert SQLite (or Redis) to Rust, because it has a lot of tests anyways, so it would be fun. I'm still waiting for GPT-4 API access though :(