Nothing is being constructed by the end user. A music album is a finished product, encoded into bits from an original creation by the author. This is a side-effect of how computers innately function, and doesn't change the fact that authors are -not- selling recipes to build products, they are selling finished products. There is no difference ideologically between selling an LP or a CD or a zipped download; the encoding and distribution mechanisms are different, but the customer still purchased the same thing: a complete product that can be played by equipment that understands how to decode and play it.
If someone singularly came up with a song, then of course they are the singular owner. Making art and music is a complex process, and specifically with music production one ends up with things that have never been constructed in that particular musical and instrumental arrangement, that key, with those musical ideas, those rhythms and note placements, etc. To say that ownership is just impossible ignores essentially -all- of the work that goes into making things like music. It's not like someone just pushes a button and calls it a day...
"Pretending its the same leads to many logically nonsensical things"
No, companies will always make absolutely ridiculous claims for copyright. Whether it's digital or not. This is separate to the idea of ownership of something whether digital or not.
"All of art is derivative thus endless copyright would cede all of the creative universe"
No one is arguing that people can claim copyright ownership on any and all works that may have been inspired from it. This is a strawman argument and also has nothing to do with digital vs physical copyright. It also completely ignores that songs, etc, are much more than mere constructions of notes.
The current implementations of copyright protection are pretty bad.. But that doesn't mean the idea in general is bad. Artists, just like anyone else, need to get paid for their work. You and I do not automatically deserve things just because they are distributed electronically now. Artists still deserve to have ownership of the things they create, even if they distribute them electronically.
No one is forcing anyone to go out and buy music or other art, it is an elective choice because one specifically desires that exact sound, which can be distributed as bits now. However, people aren't going out and "buying bits", they are buying specific products. The fact that things can be represented as bits is entirely irrelevant to both parties aside from not needing to lug around physical items.