Heh - I make no claim to be a classicist. I don't have the languages under my belt for one and secondly my historiographical base is 20th century diplomatic and economic history.
In any event, I was pretty clear in my review that the movie was mythic, not historical (It's set to a hard rock sound track, for starters). Movies are better at " mythic" - "Gods and Generals" or "Saving Private Ryan" do not mythologize any less than 300, even if their details hew closer to reality.
"the last five hundred years made liberty, not Grecian slave cultures nor other precious mythologisation of the pre-Xian past"
True but that doesn't mean the chances were any less slender in a more modern time frame. If they were then political liberty and liberal economies would be the global norm.
Give Napoleon a few minutes head start at Waterloo and he'd have smashed the coalition. A few months delay in America's entry into WWI would have resulted in a German victory. These things were were not foreordained conclusions.