Actually Robert Browning, from Andrea del Sarto. "Less is often more" was used still earlier by Christoph Martin Wieland.
Misattributed
“More and more we are into communications; and less and less into communication.”
The Shoe workers' journal, Volume 16 (1915) p. 4
Variant: What does labor want? We want more school houses and less jails. More books and less guns. More learning and less vice. More leisure and less greed. More justice and less revenge. We want more … opportunities to cultivate our better natures.
“A specialist is a man who knows more and more about less and less.”
Speech before a gathering of physicians (circa 1922) http://books.google.com/books?id=qYIHAAAAMAAJ&q=%22a+specialist+is+a+man+who+knows+more+and+more+about+less+and+less%22&pg=PA35#v=onepage
“We live in a world where there is more and more information, and less and less meaning.”
Source: Simulacra and Simulation
“[…]schools reward people who study more and more about less and less.”
Rich Dad Poor Dad: What the Rich Teach Their Kids About Money-That the Poor and the Middle Class Do Not!
“We are all old children, more or less serious, more or less filled with ourselves.”
