Is that a bad thing? Libraries like Tensorflow were never going to be written natively in Python, but it's a reasonable choice for deployment (whls can be installed anywhere), for user interface (Python can interop with anything), and for overall ergonomics/ecosystem (import antigravity).
No, I'm arguing that it's a good thing. There are some who argue that a language's tooling should be written in said language, but I argue that that's putting the cart before the horse, that the tooling should be fast and efficient first and extensible second, because there are many more who are tool users than tool creators, so we should optimize for the former. There is also no reason that someone who is so interested in tooling could not also learn the tool's language, like Rust, and contribute that way.
I guess there's kind of a vague philosophical argument to be made for dogfooding, but that's perhaps more relevant early on in the lifecycle of an ecosystem.
On the other hand, if Python had been really committed to dogfooding at the level of something like golang, then the primary implementation would look a lot more like pypy than it would like cpython.
