Balderdash! The '60s had some great films..."THE RUSSIANS ARE COMING,THE RUSSIANS ARE COMING", "THE PAWNBROKER",and "2001; A SPACE ODYESSEY"; to name but three.
"The Flight of the Phoenix" Bullitt....many others
I didn't say there were NO good films. Just weak compared to the 1950s. All the great studio system directors were aging and in decline. The result was plastic films from great directors like 'Man's Favorite Sport', 'Torn Curtain' 'The Sandpiper'. Those three from men who had given us 'Red River', 'Vertigo' and 'Meet Me in St Louis'! But even the great popular successes of the early to mid 60s like 'Charade' and 'The Great Escape' strike me as stiff and and uninspired. Trivia: The Pawnbroker was the first mainstream American film with nudity.