Not entirely true. Google released Gemma 4 models recently. Allen AI releases open Olmo models. However, you're right that the Chinese open models seem to be much better than others - Qwen 3.* models especially are punching above their weights.
Pun intended?
The three American labs don't release big open source models. Except gpt-oss, i guess. It's an absolute shame how far the us has fallen in this space.