What is the secret sauce Claude has and why hasn't anyone replicated it?

I've noticed something about Claude from talking to it. It's very very distinct in its talking style, much of an individual than some other LLMs I know. I tried feeding that exact same system prompt Sonnet 4.5 to Qwen3.5 27B and it didn't change how it acted, so I ruled out the system prompt doing the heavy lifting. I've seen many many distills out there claiming that Claude's responses/thinking traces have been distilled into another model and testing is rather. disappointing. I've searched far and wide, and unless I'm missing something (I hope I'm not, apologies if I am though.