Reason why USA's entrepreneurial venture ecosystem is so good

I recently saw a video of Jeff Bezos (Founder, Amazon) tell about *insert title here*. He quoted "Availability of an abundance of 'risk capital'".

Apart from funding, is there any other reasons due to which we aren't able to build a good a DeepTech entrepreneurial ecosystem?

PS - I am not talking about OpenAI wrappers. I'm talking about individual LLM tech like DeepSeek v2 or Claude LLM.