[Gormo]

Not sure I'd agree. "Record album" never specifically referred to anything physical, and just means "collection of recordings", regardless of what medium is used for them.

The term "album" by itself did originally refer to something physical -- a collection of photos bound into a book by a glue made from egg whites ("albumen") -- but the semantic shift to "album" meaning any kind of collection offered as a single unit happened well before "record albums" were a thing.

But the term "box set" has not experienced a comparable semantic shift, and still implies the presence of an actual box.