I just came across this quote from Niccolo Machiavelli in The Prince on the Gristmill weblog which I think is worth chewing on:
It must be considered that there is nothing more difficult to carry out ... than to initiate a new order of things. For the reformer has enemies in all those who profit by the old order, and only lukewarm defenders in all those who could profit by the new order, this lukewarmness arriving partly from fear of their adversaries ... and partly from the incredulity of mankind, who do not truly believe in anything new until they have had an actual experience of it.