Why are movies so damn L-O-N-G these days?

Is it to sell more pop corn and crap?
It is rare for a Hollywood movie to be under 100 minutes, usually around 2 hours, even comedies. Take   Judd Apatow's "This is 40".This very slight movie went on for 134 minutes!!!
Hollywood movies in the 30's, 40's, 50's could tell a story in 100 minutes or less. "The Wizard of Oz" 101 minutes, "Casablanca" 102 minutes, "His Girl Friday" 92 minutes, "The Maltese Falcon" 100 minutes.
"Warm Bodies" (2013) is an example of economical film-making. We had a zombie apocalypse, a love story and post apocalyptic redemption and rebirth, all in 97 minutes (including 2 minutes of end credits).
Another example "Philomena" (2014), a beautifully told tale in 98 minutes.
More please.