“Folly.” The abstract concept is put for the people who are fools.

“in many high positions.” That is, in many exalted positions or places of honor. For example, at a feast, to be closer to the guest of honor or host was to be “higher” than others (cp. Luke 14:10). Ecclesiastes 10:7 gives the example of servants on horses while officials walk.

“the rich.” This refers to people who are “rich” physically and mentally, for example, in wealth and/or wisdom.