Envy is the completely wrong framing, it is about fairness. If you design widgets and 99 people build them and everyone works the same number of hours, then the fair share is 1 % for everyone. One percent of the work, one percent of the profit. If you take 2 % [1] while everyone else only gets 0.99 %, that is unfair. And look, the difference for each individual is tiny, 0.99 % or 1 %, that makes it easy to dismiss despite being the source of the unfair inequality.

[1] 1.99 % if we want to be precise.