I BUY ONE CD A MONTH AND I AM HAPPY
I BUY ONE CD A MONTH BECAUSE IT IS ALL I CAN BUDGET
I BUY A LOT OF MUSIC EACH MONTH
I HAVE A LARGE LIBRARY ALREADY
I HATE CURRENT MUSIC
The fact is that there is still a wealth of great new music no matter your which genres you like. However, even if you don’t want to hear new music, there is a wealth of older music available. For example, if you have a couple Rolling Stones albums, you may be delighted to have access to all (or nearly all) of their music. Even if you don’t like Rock, the situation applies to every genre. Yes, you will occasionally encounter an artist that isn’t available on the subscription service you use, but you can still always buy their albums if you really want to hear them.
I AM YOUNG AND WANT TO BUILD A LIBRARY
The first is that there may be ~30 million songs available, but that doesn't mean they have everything. For example, The Beatles are not currently available via on-demand services. However, you could more easily fill in those blanks than the other 30,000,000 songs that the service has available that you don't.
The second is the lack of ownership. If you paid for the service for 10 years at an average of $100 a year, you could have bought a thousand dollars worth of music you would own forever. With streaming, if you stopped paying, you would no longer have access to the music. That brings up the point of whether you listen to music for the experience or treat it as a long term investment? Personally, I own about 1500 albums. At an average cost of around $10 an album, I am in for $15,000. If I had put $120 a year toward streaming instead, I would have had access to millions of albums for 125 years. Since, I probably won't live for another 125 years, I could take that extra money and put it toward artists like The Beatles or put into a savings account for that matter. As I mentioned before, if you don't buy a lot of music, you really don't need streaming unless you simply want it for convenience.
Third is that most streaming services use audio compression. Spotify uses 320k Ogg Vorbis files and Apple uses 256k AAC. On some songs, on some systems, you might be able to tell a difference between the two if they are played back to back, over and over.
However, many ABX tests have been done on the Hydrogen Audio forums and they believe transparency for MP3s occurs at ~192k and even lower bit rates for Ogg and AAC. In my humble opinion, once you get to ~256k, the main issue with sound quality is related to the mastering.
As a side note, many CDs were mixed with the "loudness wars" in mind. As a result, they have compressed dynamic range, and in some cases, flattened wave peaks. While Apple uses 256k AAC, they are unique because they could have the benefit of artists that have supplied "Mastered for iTunes" versions of their albums. If they use these versions, and currently there is actually nothing on Apple Music indicating when they are "MFiT", the theoretical sound quality loss from audio compression could be equalized or bettered by the decrease in dynamic range compression.
All that being said, even for audiophiles there is Tidal and other services that stream in lossless formats if they don't mind paying twice as much for the service and living with less features than the competitors. They are even working toward Hi Rez streaming that might even make Neil Young's golden ears happy.