I think this thin/thick thing has become a moot issue now. When I was in the market for a new car, I was looking at the BMW X3, and it turns out that all new BMWs and Audis, except for the racing versions, are now using 0W-20. Every car is trying to improve its MPG and oils with HTHS viscosity ≥ 3.5 cP are becoming a thing of the past, regardless of whether you live in US or Europe. TGDI engines, hybrids and plug-in hybrids, and EVs are becoming common for the same reason.
Moreover, 0W-16 is now becoming mainstream and 0W-20 is a "thick oil" now.
If I had a new car and was worried that 0W-16 or 0W-20 was too thin, I would probably only go up to a synthetic 5W-20, which usually has a base oil as thick as that of a 5W-40 and considerably thicker than that of a 5W-30 and the HTHS viscosity should be sufficient for most applications unless you are really pushing the vehicle to extremes.
Moreover, most new cars come with free-maintenance periods and you don't get a say on the oil choice.