Copyright was designed as a sort of checks and balances between artists and consumers of art. Maybe that is not the best schema, but it is the one we have had for hundreds of years. Typically, copyright law has landed somewhere in that spectrum, but the unintended consequences of DRM, the DCMA, and subsequent judgments has been to create a hard skew on the spectrum not towards artists, but towards copyright holders: publishers, studios, corporations, and those few artists who choose to keep their copyright.
Much of Doctorow's supporting evidence is not very good evidence, as it is mainly cherry picking and oversimplification, but the core problem he is addressing is very real. The balance of powers between copyright holders and consumers has been disrupted, as the limitations of copyright can be circumvented by copyright holders.
Update: I have had a fairly long email conversation with Bill Rosenblatt about the assumptions and argument in Doctorow's article, and it seems that Doctorow's claims are even weaker than I had assumed. Yes, there are some foundational truths in the argument, but the rest is extrapolations that are largely unjustified.