I feel like there's numerous database companies that rewrote an existing database faster/with slightly better features and turned it into a successful product. Just about all of the successful ones really. It's a market where "build a faster horse" has been a successful strategy.

Certainly some of the newer succesful database companies are written in more modern languages (for example go with cockroachdb, go originally and now rust with influxdb) but it's wrong to call these (or really any language) faster than C/C++ just more productive languages to develop reliable software in...