I believe what
igorsk is saying is that it's possible in theory, but nobody has done it yet. In
this thread, we discuss the only current method of converting DRM-protected PDF files to other formats: using software to make screenshots of the entire file and OCRing them.
It certainly would be nice if there was a simple solution like there is for other formats, but at the moment the long, complicated, error-prone process mentioned above is all we've got. Not really worth the trouble.