Once historical dramas were about how we looked at our collective past. Now they're about how we look at aging movie stars.
It's not as if we're living through a golden age for historical dramas, either – the opposite. The number of films set in the past is at an all-time low. Instead, what is happening is that actors hungry for Oscar-calibre roles are frequently having films built solely around those roles – and the rest of the film can go hang.
Two current examples of this phenomenon are lee Daniels' The Butler and Jobs, in which Ashton Kutcher walks around spewing Jobs-esque banalities like "We gotta make Apple cool again!"