Europe has pretty strict environment rules, but they are not normally abused to stop a project by just delaying and litigating it forever.
In the US, the actual care for environment is lower I think BUT you can just drag out a project forever on enviro issues.
SF bike path was sued for not doing enough of an enviro study, took another $1M, maybe 1-2 years to get it going again.
This is one (small) factor.
Another - in the EU most folks are part of unions, but the unions are not such a political machine. So in the US you can get total nonsense in staffing, no show / low work jobs - the EU puts up with a lot less of that from casual observation (at least germany, maybe Italy / Greece have more of an issue here). Unions seems reasonably productive in Germany - does someone have more data here? I don't know the details, just my impression.