I think it just shows how culture has shifted — in 1964, the choice was essentially TV, movie theaters, or books.
You had a captive audience, and because they had less choice, you could make a DR STRANGELOVE a hit.
Cut to today, and the options are endless, and much lower brow.
I think Digger's low review score is a reflection of the academic collapse of humanity in general. The movie is a risky achievement in telling the truth about how we use art to justify our lack of action.
But... it takes a while to pay off. You wouldn't get it if you disconnected from the movie early on. It demands attention to detail, focus.
Iñárritu and Tom Cruise respected the audience's intelligence and paid the price.