The data does not support your statement. From a startup report just four days ago:
The United States alone generates 46.6% of all startup activity worldwide, nearly half of the global total. Together with China (9.2%), the United Kingdom (5.6%), and India (5%), these four countries account for 66.4% of the absolute global startup activity.
I will give you that Israel in particular has a strong risk taking culture, as does Singapore and Estonia. And there are a lot of startups coming out of there.
But overall the US has way more risk taking.
And like I said at the very beginning, there are of course exceptions. Yes, every culture has some brilliant risk takers. But at least until recently, many of them came to the USA after they got successful.