Is it likely that the Bluths (and Fünkes) will never reunite on the big screen? Yes. Is it certain? No. In fact, this presumption that the film is dead is hardly different from the hype that the film was alive in the first place (begun at Juno junkets, I believe). And I tell you now, mark my words, this isn't the last time the interweb will be filled with excitement or disappointment about another status update from another cast member.
What I find more interesting than Cross' pessimism regarding the film is his argument for why it can't happen. He says that too much time has passed. That everyone has aged. But four years is really not that long in terms of spin-offs and sequels. We Arrested fans would be fine revisiting the family wherever they are in five, ten, maybe even thirty years. It took a decade for the prematurely canceled Star Trek series to spin-off into a film. That said, perhaps a long enough wait could result in a film that takes the cast into space, for a Bluth Company expansion into housing communities on the moon.
Yeah, that'd be pretty silly, but they'd have to do something big to cover such a high level of anticipation. The only reason the passing of time is an issue for a project like this is the buildup creates unrealistic expectations. Unless, that is, the impatience takes its toll and the hype-boosted (and hype-boosting) demand decreases. Then an Arrested movie could finally hit when people have calmed down about it.
Or, like Cross prefers, there should just be a reunion on TV one day, whether as A Very Bluth Christmas or as something like the Seinfeld reunion on Curb Your Enthusiasm. Either way, I continue to be optimistic that we haven't seen the last of Arrested Development. Even if it's just a spin-off show or movie in which Bob Loblaw, Carl Weathers and Annyong share a beach house for a summer I'll be more than satisfied.