How's about a compromise?
European customers use European cloud services, who encrypt our data and store it with the cheapest cloud providers on the planet.
Enacting Uncle Sam's Patriot Act would be useless,
Okay, yes the service on a service will add cost overheads, but a large enough European service would surely have some leverage on price/GB.
Another advantage would be the common interface presented to users by the European service, regardless of which cloud provider is holding the data, which could be seamlessly moved to another storage provider as and when required.
Slowly the EU provider can onboard its own local storage as demand increases.
Like the ingredients on a food label, I want to know where my data is being stored, and if it's on an American server, and it is readily readable by the NSA, then it isn't covered by GDPR, so I'm not buying into it.