Expecting them to have lifespan and protection of the property under one's house, or to even be analogous to that property, is delusional.
That will disadvantage more produced, machine-assisted music that is hard to recreate live (or unconvincing when played at a moderate volume), but if there's anything the internet has taught me, it's that people will make that stuff for free, extremely well.
I'm doing a summer internship in San Francisco and one of my favorite parts of living here is being able to see fantastic local music in small venues. I've been going to a cafe in the Mission where I can just hang out after work and listen to a jazz group play from around 8:30 until midnight.
I noticed that as a result of seeing live music in my spare time, my consumption of recorded music has dropped dramatically. I pretty much only put on my headphones when I go for a run (I will occasionally listen to an album while I'm programming, but I prefer not to).
Recorded performances enable 0.0001% of professional and "semi-pro" musicians to earn a living from recorded performances. For everyone else, life is as it was before recorded performances: You perform live, and you may have a day job, maybe teaching music, maybe something unrelated to music.
If the money from recorded performances goes away, the impact on music as an artform will be nil.
But a quality reference book doesn't really have an analogue in music. That book can be a key tool to someone performing their profession. This applies even in a digital medium.
Whether the book or recording is digital or not doesn't really matter
Why do you think a recorded performance of a work should be protectable under copyright? It's NOT an original work of the intellect. It's a performance of what is often someone else's work. Just because it is recorded, should it be protected? Does the technological innovation of recording make it protect-able? And, if so, shouldn't the technological innovation of infinite copies at zero marginal cost make performances un-protectable?
I don't see any difference in a book and an original music recording in terms of why one should be subject to copyright and one not.
Whether recordings or books are protectable in practice is another matter, as it is very easy to make digital copies of both.
But if one takes the stand that an author of a book (be it an e-book or a printed one) has the right to set a price for a copy for her work, and benefit from protection by copyright if she so chooses to, I don't see how a recording of an original piece of music is any different.