What is the implicit argument about America in Seabiscuit?

I think that one of the underlying arguments about the culture
of America in Hillenbrand's work concerns the strength and resilience of American character. 
Given the fact that America is a fairly young nation in comparison to other nations on the world
stage, there is not as much written about national character and what defines a part of that
identity.  Hillenbrand's work seeks to bring out a part of this complexity in its suggestion that
the notion of endurance and perseverance is something that is driven into American DNA,
invariably leading to triumph.  Seabiscuit is a horse that few wanted and even fewer understood. 
The trainer is discarded as useless and the owner is deemed as a failure at businesses and his
personal life, while the jockey is seen as past his prime.  In the end, all of these forces
converge to construct a narrative as one that helps to bring out the vision of "the American
Dream" and the idea that America, emerging out of the Great Depression, has within its character
the sense of strength to last through the difficult and trying times and triumph over them.  In
this light, there is a statement or argument being made about America and its culture in
Hillenbrand's work.