This aphorism or some version of it looks to be one of the more common misattributions in modern history. Whether you credit Tennyson, Picasso, T.S. Elliot or Stravinsky, it clearly has powerful meaning across the creative spectrum. Looking specifically at the design of some great Modern chairs by great designers, we find plenty of evidence that the great designers steal.
Modern master Hans Wegner called this famous chair (below left) the "Chinese Chair" after the Ming Dynasty chair from centuries earlier (below right).
Kaare Klint referred explicitly to the works and values of the American Shaker movement when he created his classic church chair (below left) derived from the form of the classic and pragmatic Shaker chair (below right).
The architect and Domus editor Gio Ponti worked closely with the craftsmen of Chiavari, to create his own very austere version of the popular Italian chair. (Gio Ponti 699 Chair, below left, Chiavari chair below right).
Referring fondly to the Thonet bentwood chair (below right), Poul Henningsen declared in the Danish Design Publication Kritisk Revy "It does not try to be false or mendacious in any way". By using steel, Henningsen was able to remove and combine features to achieve his own design (below left). In my opinion, this example is the only one of these four where the virtues of the changes are in question. It is just difficult to improve on Thonet..
So, stealing ideas is apparently just fine. There is a humility in acknowledging that those who came before us came up with some great solutions. So lets get to it...just steal the good bits and make it better..