It's harder to determine the cause, though. Contrary to popular opinion, I believe that work ethic, level of dedication, drive and regulatory climate wrt. employee protections, consumer protections etc. has something to do with it.
But this is just a small part of the question. We also don't have solid access to investors and capital, a business/startup-friendly tax & regulatory climate, a home market of 300 million customers, a culturally compatible potential employee pool of 300 million, many of the world's greatest universities, thousands of successful entrepeneurs who participate in the business climate, entrepeneurial success as a prominent cultural trait, excelling in your chosen profession as something to be lauded, bureaucratic & legal support for companies that are about to become successful, a relatively judgement-free climate with regards to high compensation for successful professionals etc etc etc.
It's hard to say if the value of not having business/professional success, or even long hours as a primary cultural value is key when compared to these other elements.
I'm pretty confident that e.g. "The Law of Jante" easily trumps the lack of a 50-hour workweek as an impediment to success, but there are probably also downsides to not even having the latter as an option if it feels necessary.