IMHO there's also something in the culture that favours startups in the US vs Europe - my feeling is that in Europe most of the avenues for social mobility were locked down tight by the elite a long time ago, whereas due to relative youth of the US as a nation that process of entrenchment is still underway.

Don't overestimate the difficulty of screwball EU regulation. The blighted cookie law is really the least of it. Even just selling something over the internet inside the EU is so difficult due to the disastrous VAT rules that you practically have to pay third parties to handle it for you, at least at the start.

There are several basic problems. The EU sees tech firms as a foreign source of money that it can squeeze "for free" because there are so few tech firms in Europe to start with. So it passes hostile laws all the time that make business hard under the assumption that big companies can handle it anyway. The Commission does not really care about small companies but the problem is replicated at the local level (UK and Ireland being notable exceptions in my view). The attempts in Spain and Germany to force search engines to pay newspapers is a good example of European countries killing off their own startups in an attempt to extract money from Google and Facebook.

The second is that it gets caught up in politics a lot. The EU places its political priorities first, always. One of the primary ways it achieves its primary goal of replacing European countries with a new super-state is passing lots of EU-level law. It spends huge effort finding places where it can create new regulations, even if none are really necessary.

The "right to be forgotten" is a classic example of the issues here. A right that was discovered by the EU's courts, then written into law by people who do not answer to any voters (thus have no incentive to keep regulation in check), which basically makes it impossible to create a startup search engine of any kind. The EU cookie law is also like that.