That comparison with a library is a good one. But today you have all these audio books which is the equivalent of learning music by ear.
Maybe. However, every audiobook narrator is reading. Of all audiobooks, is there one author that doesn't read?
In order to write clearly, one needs to think clearly, and that level of thought typically begins with reading. After all, reading is "fun-damental," right?
While there are always exceptions, they are rare.
Consider the fate of the Beatles without their 5th member. George Martin was their composer, arranger, and producer for their most important musical contributions. Martin's reading, writing, and aural musical gifts were significant factors in the Beatles' success.
And, regardless of notation type, one still needs to read. Tab, Nashville Numbers, chord charts, etc, all require reading skills. Standard notation is most complete and universally known.
Listening to an audiobook or music recording is passive. We can surely learn from those. In music, we learn our instruments by playing, assimilating information to perform. The assimilation methods are numerous, using a variety or mixture of senses. The more senses employed, the better.