Microsoft, Apple, and Google also have more resources at their disposal yet Linux is doing just fine (to put it mildly). As long as Mistral delivers something unique, they'll be fine.
Linux is funded by big tech companies. IBM probably put a billion into Linux and that was 20 years ago now.
This wasn’t status quo. In fact, it can serve as an example. Why wouldn’t google or microsoft follow the same path with mistral? Being open source, it serves their purposes well.