Depends on which part of Europe. In Spain, duvets weren't even a thing in the 80s, at least as far as I know. Everyone used sheets and blankets and/or conforters. The first time I met duvets was in foreign hotels, later Spanish hotels started using them too, and even later, laypeople started using them.
They quickly gained traction (Ikea probably had a big role there) and now both alternatives are common, although I'd say maybe duvets are already the most common.
The Spanish words for duvet and duvet cover (edredón nórdico, funda nórdica) are a testament of the fact that they used to be a foreign thing, here associated (I don't know if accurately or not) with the north of Europe.
