It's not unrealistic. Several Chinese companies seem to be close behind. People thought they would never catch up to the US car industry and now look what happened.
Frankly, the US car industry hasn't set the bar very high. They were not very innovative in the last couple of decades. I think the European industry is a better benchmark, and even then the result is pretty clear.
To the best of our knowledge, these Chinese companies rely on distillation of frontier models by OpenAI and Anthropic, which isn't a method available at the frontier itself.