Yeah, I didn't mean to say it was the sole reason or even a primary reason, but it's a contributing factor. The risk-averse culture (investment and employees), and lack of exemplars of successful entrepreneurs (vs. going into banking, government, etc.) is probably the biggest problem.
I get the general perception top tier Sand Hill VCs are now willing to invest in Series B or later (and some Series A) in Europe. Costs have dropped, even in Europe, so you can get pretty far on $50-100k in savings for a seed round. So the big problem in the long term is probably risk-aversion in hiring, vs. raising money.