This view is quite superficial. First of all, I don't think that there is such a large difference across the two continents in their approaches to net neutrality: there are loopholes large enough in both laws as well as many uncertainties concerning details of implementation - The Economist ends their analysis acknowledging that the US law faces many hurdles still. Second, it is not clear that European telcos have more leverage with their governments than say AT&T (which has just managed to reassemble itself to control a large chunk of digital traffic), or say, Comcast and some other large cable networks. Third, expensive infrastructure for consumers is just as much a roadblock to innovation on the Internet than net neutrality - in fact, arguably more so. European broadband costs are much lower than equivalent service costs in the US and as a result Internet usage is way ahead in Europe compared to the US. Fourth, net neutrality is not an unambiguous good thing so that more of it is automatically better. Network management is complex and priority needs to be provided to some content to avoid congestion - finding the right balance is extremely complex. While some bandwidth needs to be guaranteed to poor new application providers, it makes sense for intense users to pay more for the infrastructure used.
Innovation on the Internet has been dismal in Europe when compared to the US. This however, does not come from overregulation of the Internet but much more from the lack of appropriate financial infrastructure and the lack an investment friendly economic environment. Indeed, the gap in innovation across the two continents is also present in other industries, not just technology.