[gbhn]

Something I think often is left out of success accounting is an advantage almost everyone born in a large, well-functioning society enjoys: access to a large, well-functioning society.

If the civilization into which Bill Gates sold software were 1/10th the size, it would have generated 1/10th the value with almost the identical amount of work on his part. There's an enormous lift given to fortunes just by the fact that they are built in the context of a civilization which is large enough to support them.

None of that is to say that either specific inherited status or personal hard work aren't huge contributors to success as well, but it takes an enormous amount of work and attention to make sure that a large, well-functioning civilization remains large and well-functioning, and that's an oft-neglected factor in how big these large fortunes become.