The story has resonated with many Americans. Author John Steinbeck named his truck Rocinante after Don Quixote's horse, in his novel Travels With Charley (which according to some of his literary heirs is indeed a novel, as much of the narrative of his travels was apparently made-up or sensationalized). We have seen this name adorning more than one RV or boat in our travels. Many folks, it seems, identify with the romantic notions of Don Quixote - even if Cervantes was in fact mocking such stereotypes.
Of course, there are other themes in the story. The story of Don Quixote is a play-within-a-play (a device Shakespeare liked to use) in that the actual story is of Cervantes telling the story, while imprisoned by the Spanish Inquisition.
This is not to say the philosophy is flawed, only that the source is rather unexpected. It reminds me of a scene from Monty Python's Life of Brian in which Brian makes offhand comments which were then written down by acolytes as being profound statements about spiritual life.