Why doesn't the EU yet have a dominant cloud provider like the US/China?

What OP means by cloud provider? Cloud is overused term. That said, we have Hezner, OVH and Scaleway. You can ask other way: why US don't have cheap well known bare metal provider.

For starters, because EU isn't a country, rather a union of countries each with their languages, regulations, and tax mechanisms.

The dominant cloud (assuming you mean cloud like AWS etc) are in fact US owned companies with massive DC's in Europe, e.g AWS in Ireland.