We can complain all we want, but I struggle to see how we can place meaningful pressure on publishers.
I wanted to say that it's like iTunes and the switch to non-DRM, but I think the dynamic is different with Amazon as there isn't any meaningful competition on the e-reader device market as there was (and is) on the MP3 player market, where DRM was a major pain and thus a driver for DRM-free.
Short of Amazon pressuring publishers to drop DRM (which could well happen, but there's not a lot of business upside to it, although do downside either), I guess it will take a viable competitor to the Kindle that Amazon can't or won't provide an app for for DRM to get pressured out by end user market force.