Jacob Helberg says one of Europe’s biggest challenges to building companies is cultural: they’re just not risk-takers like Americans are. "It's really hard for Europe to put those pieces together because the culture in Europe has not been favorable to encouraging risk-taking, which is necessary—it's the lifeblood of starting a business." "You need to have a risk-taking culture—and then they have the unit economics problem where it's just really expensive to build stuff in Europe because your…