Although the Anglican Church is a hybrid of Reformation era Protestantism and of Catholicism, I think that the US tradition of Protestantism is generally (not always) more positive and less fatalistic.

I believe that the cultures of both nations are heavily derived from their religious traditions; even if you never practice religion in either nation you imbibe its effects from early childhood in the cultural values and norms that it influenced.

For example, one of the key aspects of Protestantism is evangelism, which would not make sense if people thought they could not be successful.

So I think a lot of American culture in particular is based on this tradition that encourages optimism and repeated trying even in the face of failure. Hence the way we select heroes.

"repeated trying even in the face of failure"

That's pretty much the motto of one of Scotland's greatest heroes - Robert the Bruce:

"If at First You Don't Succeed, Try Again"

https://en.wikipedia.org/wiki/Robert_the_Bruce

In some flavors, Protestantism is quite focused on self-scrutiny and skepticism about human nature, making people suspicious and even actively hostile towards supposed heroes.

Other flavors of Protestantism seem to have completely lost that, though. Evangelical Protestantism somehow inculcates a need for leaders to love and worship and an ability to completely suspend rational judgment about them. Their relationship to charismatic pastors and other leaders is a mystical, ecstatic experience that they have an unlimited appetite for. No matter how many times their leaders are shown to be flawed, and in many cases quite detestable and corrupt human beings, they eagerly look for the next leader to worship.

Two stereotypes that illustrate the extremes of this massive cultural difference in Protestantism are the rich WASPs of the northeast and the poor Southern Baptists of the deep South.

WASPs know that heroes are myths, and are unsurprised when the real people turn out to be real pieces of work. Southern Baptists kind of know this on some level -- I think they're actually a bit attracted when a man has a whiff of charlatanism about him, because it shows he knows what they want -- but when they choose their hero, they give themselves over to complete and sincere belief in him.