Films have been speeding up for a century, in two ways. Editorial geography disappeared in the 1960s. Editorial geography example (not mine): Bogart gets phone call. Bogart gets up, walks out door. Bogart walks out door of building, gets into cab. Scene of Bogart in cab. Bogart gets out of cab, pays cabbie. Bogart walks into apartment building lobby. Pushes elevator button. Shot of elevator indicator coming down. Doors open. Bogart gets in. Shot of elevator indicator going up. Elevator doors open. Bogart gets out, walks down hall, rings doorbell. Lauren Bacall opens door. Bogart goes in. That's editorial geography. At one time, it was felt that audiences would get lost without such a sequence. Today, writers and directors would skip directly from the phone call to an interior shot of the apartment. Jean-Luc Godard's "Breathless" (1960) is said to have put an end to that.
Related to this is average shot length as a metric.[1][2] "2001" has an average shot length of 13 seconds. At the other extreme are the Bourne movies, which are now down to around 1.1 seconds per shot. James Bond movies have sped up over the years, with "Dr. No" at 7 seconds and "Die Another Day (2002)" at 2.4 seconds.
This is an industry-wide trend.
Trailers are insane. Trailers routinely break the 1 second barrier today.
So there's been a speedup in two dimensions - removal of unnecessary context, and shorter shots. To a modern viewer, 2001 looks quite slow-paced.
With enough short shots, films can conceal the lack of a plot. (This is a problem with effects-heavy movies. After you leave the theater, you realize the plot made no sense. But it was a great effects demo reel.)
[1] http://www.cinemetrics.lv/database.php
[2] http://unspokencinema.blogspot.com/2007/01/average-shot-leng...