Not GP, but: Critical mass. Accepted in many domains as a valid first class solution. Memory safe. Has that depth of modules now that you can `go get` most things off the shelf. Easy to get a team up to speed, leading to wide adoption.

It is like the Python of statically compiled languages to me, but with way more safety rails and things you need as your code base grows.

There is just demand for it in general from what I see.