Is DRM really inevitable for streaming video ? I can listen to my music as much as I want, unrestricted, without DRM, through deezer. And that's a premium service. They seem to be doing just fine.
Besides, spotify uses flash for their webplayer, probably for DRM as well. Yet there exists an open source spotify client, despotify, that probably would make it very easy to download the music as MP3.
In the end, DRM just means making your client's life a pain.