[JPLeRouzic]

I think the most simple reasons to tell that DRM can't ever work, are that:

First DRM proponents have gone very far to protect their content. It costs them a lot of money and from a economical point of view it is difficult to see how DRM help them making more money.

Second: The guys who use pirated stuff would anyway not pay if DRM was working, so why the media industry would bother to struggle with them?