Europe has some pretty dense cities with roads that go back centuries. Some of the larger ones now try to control pollution by charging fees to drive there, and exempt EVs. As part of that all, they have a much lower sulphur content requirement on fuels than we do in the USA. As a result of that, it costs a little more to refine their fuels and makes them more restrictive on where they come from. But, it's not a major reason why the fuel costs more...it's primarily because of the taxes applied.
As a result of that sulphur content in the US fuels, testing done elsewhere in the world to verify proper operations does not always catch the effects of stuff like that sulfur content in the fuel. I'm sure that there are other details. One, I think is relevant to the i3 is the use of the original composite motor mount. As I understand it, the failures were primarily caused by the severe impact stress on it if a wheel lost contact with the ground, the EV motor rapidly spun it up, and then hit the ground again. That abrupt slowdown could crack the motor mount or the bolts holding it. While you can find bad roads anywhere, after living in Germany for a couple of years, my take is that in general, their roads are pretty well maintained, and you do not see significant potholes in their roads, and, in general, the drivers seem a bit more skilled. Throw that same vehicle into the USA, where potholes and road maintenance has been neglected for ages, and the situation where the motor mount would be stressed becomes significantly more pronounced. IOW, that problem didn't show up in the testing. You could argue that the testing was inadequate. But, I think that the added taxes on their fuel does offer them the opportunity to apply funds to keep the roads in better shape than we do with ours here. People complain about shredding tires, broken springs/shocks/wheels, misalignments, and general wear that ends up costing a fair amount of money, but won't agree to raise the fuel tax here to help pay for maintaining the roads. Now, throw in increasing EVs who aren't buying fuel but use the roads, and having money to pay for repairs could get even worse. I expect, somewhere in the future, that people will end up paying a per mile tax for road use similar to the taxes some big trucks now pay applied to EVs and hybrids to account for their contribution to damage to the roads. BEVs and hybrids tend to be heavier than their ICE compatriots which leads to more wear on the roads, but are paying less than their share of the costs. One could argue that they're less of an impact on the environment that could help to offset it. This will become more of an issue as the adoption of EVs or H2 powered vehicles increases. Something to think about...
2014 i3 BEV, 2021 X5 45e
(The i3 will be sold soon, <17K-miles, interested?)