I think that's an overgeneralization. We've seen all the American models be closed and proprietary from the start. Meanwhile the non-American (especially the Chinese ones) have been open since the start. In fact they often go the opposite direction. Many Chinese models started off proprietary and then were later opened up (like many of the larger Qwen models)
> We've seen all the American models be closed and proprietary from the start.
Most*.
OpenAI, contrary to popular belief, actually used to believe in open research and (more or less) open models. GPT1 and GPT2 both were model+code releases (although GPT2 was a "staged" release), GPT3 ended up API-only.
> We've seen all the American models be closed and proprietary from the start
What about Gemma and Llama and gpt-oss, not to mention lots of smaller/specialized models from Nvidia and others?
I would never argue that China isn't ahead in the open weights game, of course, but it's not like it's "all" American models by any stretch.