I should clarify: the US STEM workforce has historically been very white and very male. That's the body of talent that has been languishing, and the data proves it.
That would sound a lot like the languishing native STEM talent in the US if it weren't also for the fact that most of the DeepSeek team doesn't have PhDs.
That's just it: American tech companies aren't staffed by Americans anymore. Liang Wenfang, the founder of DeepSeek, made the point that he values developing domestic Chinese talent over importing foreign experts. It seems to have worked.