Income distribution and wealth distribution are not the same. It is perfectly possible to earn $500k/year (which would put you in the top 1% of income distribution that this article is talking about) and spend every penny of it, leaving you at the end of the year with the same amount of wealth that you had at the start of the year.

Similarly, it is possible to earn $200k/year (not in the top 1% for income) and save very aggressively.