Rod Stradling is thinking out loud in his latest editorial comment on the 'Musical Traditions' website. I hope he is wrong about the future of CDs. He writes:-

The Future of Optical Drives and CDs

The decision by John Lewis stores to stop stocking DVD players has prompted me to consider the future of the optical drive in modern computers. Clearly, the removal of optical drives from laptop computers - and the lack of them in tablets and smartphones - means that, in the very near future, downloads are going to be the only practical way to pass music from one person to another. And that means from a producer to a purchaser, of course.
This was one of the two main reasons that I started making the contents of our CD publications available as downloads (sound files as MP3s and booklets as HTML files) back in 2015. The most pressing reason was to try to ensure that, if I was unable to continue with Musical Traditions work, both Magazine and Records, for any reason, someone else should be able to continue to make it all available with very little input beyond keeping up the payments to our ISP and Hosting providers. The small income provided by the downloads should be able to cover these payments.
The other reason was to do with the first paragraph above - the future demise of the optical drive and thus that of the CD. One problem raised its head as a result: what format to use for the downloads? This problem was discussed in various Editorials in 2015. That discussion focussed mainly on the format of the CD Booklets ... which I consider to be almost as important as the songs and tunes. At that time it seemed that there were so many types of E-Book, and none that were then dominant, and that the necessary creation software was pretty expensive, that the humble HTML was about the only one that was universally readable. If that situation changes, I shall have to have a re-think.
But the choice of MP3 as the sound file format was very simple ... it was universal. But, just three and a half years later, the demise of the MP3 is being discussed by those who discuss such things. Flac appears to be the format of the day. FLAC (Free Lossless Audio Codec) is a musical file format that offers bit-perfect copies of CDs but at half the size of the .wav files that produced them. MP3s, on the other hand, are about one tenth the size of those .wav files. One may feel that, in the age of Terabyte hard drives and Broadband Internet, such considerations are of no real consequence. I'm not so sure - big is not always beautiful - and .wav files do take a long time to download, and are problematic to send as attachments.
MP3 is a lossy format, which means parts of the music are shaved off to reduce the file size to a more compact level. It is supposed to use 'psychoacoustics' to delete overlapping sounds, but it isn't always successful. Typically, cymbals, reverb and guitars are the sounds most affected by MP3 compression and can sound really distorted when too much compression is applied. As you may have noticed, MT CDs don't feature all that many cymbals, or reverb guitars, and so our use of MP3 does not cause these problems. Rather more to the point, very few of them feature recordings made more recently than the 1970s, and so don't have a frequency range that would be better appreciated at higher fidelity. Indeed, most feature only a solo voice or instrument - so I did a little experiment. I ripped a solo voice track and a solo fiddle track from a 2018 commercial CD, as .wav, .flac and .mp3 and listened to them played quite loudly. I could detect no difference in the sound. I then did the same with MT CDs of quite old recordings ... with the same results. As regards size, an example track produced a .wav file of 42,082Kb, a .flac file of 22,642Kb, and an .mp3 file of just 4,307Kb. I did not find that big was beautiful, or beneficial. Again, if this situation changes, I shall have to have a re-think.
                                           Rod Stradling - 29.10.18

His excellent website is at https://www.mustrad.org.uk/