I don’t know a Manolo Blahnik from a Louis Vuitton but then I’m not well-heeled either!!!! :)
If you have an imagination as tame as mine, you’d assume that the origin of “well-heeled” comes from the plush set in their haute couture.
But no!!! The origin of the expression lies in the cock-fighting days of the yore when the contesting birds were equipped with the best spurs to cause the most damage. From there, it moved to the frontier days in America’s history when men carried concealed pistols in their boots. And as language knows no bounds, from concealed weapons it came to be used in reference to money (why?? don't know!!!!), as in the current usage.
Source: answers.com, Google Images