Some international artists in the past and currently—Rolling Stones, AC/DC, bands that are massive historical bands—don't make their recordings available for those streaming services, but they are in the fortunate position to be able to say “you can't have it”. In many cases, some of them prevented their music from being available on iTunes for many years as well.
The problem, if you're a developing or a current artist, is that it's not as though you're making the sales up in other areas. In other words, if you withhold your music from a streaming service, you aren't automatically selling more CDs or even the same number of CDs or the same number of digital downloads. Basically, what is happening is that those sales are eroding regardless, so whether you have your music on a streaming service or not, your sales are decreasing.
Most people I think do it. As someone running a record company, I was certainly resistant at first at making my music available on streaming services, especially after I got the first royalty report. But to not be there means that you're not living in the current world of the way people consume music.
To the point earlier about YouTube, I know that probably 80% of the people who experience the artists whom I work with do so on YouTube or some service like it, from which I get paid a minimal amount or next to nothing. But it continues to build the artist's profile in the hope that, if there's a perfect storm and we get a radio hit or get a song on the video channel, the YouTube streams are—