Indeed it is..
Software development is not an exact science.. You can only plan so much, and draw a conclusion in the form of an estimated release date.
But along the way, all kinds of neat (and most likely not so neat) surprises pop up, that can make the previous estimate a little optimistic. And it usually only works in one way.. shifting the release to a later estimated date.
This is not unusual, it happens with a lot of WIP's that I have seen or been a part of..
But it's when people on forums, start putting out dates that were mentioned once as very early guestimates and telling everyone it will be released for sure, that people pick up on that and make a fuss..
Simple fact is, that there are many more developers NOT keeping to the estimated dates, than there are that do manage to pull it off... (and I reckon in the latter case, often there is pressure from certain fronts, that makes for worse quality, and I know what I would prefer..)
Fred.