Let me throw this one out there to see what you all think. I'm not saying that the following is 100% where I currently stand, but it's one of many lines of thought I entertain on the subject of hybrids (as I debate the issue with myself.)
Hybrids to me were always more of a journey rather than a destination. A bridge technology from 100% dependence on gas to something much more agressive (like a plug in or full EV). The industry seems to be spending an awful long time on this bridge, and keeps making unfulfilled promises about when we'll reach the other side.
I also think the elephant in the room is this: what happens when large-scale battery replacement becomes an issue with these cars around 2010-11. Even now, those with high-mileage hybrids (that are beyond the warranty) are getting hit with extremely high replacement costs ($3000+). I personally think that the lack of affordable battery replacements will be the near-death of hybrids. No one will want a Civic-class car that has a
known $3000 repair in 8-10 years to keep running.
Now I think if batteries become a non-issue (which I hope they do), I think this "bridge" we're on could in fact be sustainable as a longer journey and hybrids could continue to grow in popularity. But if the batteries are an issue, some of these critics may not be as far off as we'd like them to be.