No, I really think you're mistaking this. Some of the easiest ways to become wealthy - or let's say "financially independent", because it's a more clear-cut term - are doing useful and well-compensated work, that is definitely not "great work" in the essay's sense. Think dentists and most doctors and lawyers, and also lots of different kinds of "businesspeople", including software engineers at big successful companies. Think about the people you see on a private golf course that they have a house next to; those people are all wealthy, some of them inherited it, sure, but many of them just plugged away at lucrative jobs and saved and invested well. That's not what the essay is talking about. It is a much easier way to achieve financial success than attempting to do "great work" in the essay's sense.
Personally I have had a tendency to waffle back and forth between the ambition to "great work" and the ambition (and at times, necessity) to do lucrative work. And for me, thus far, the two things have been almost entirely negatively correlated; I have given up the lucrative path to seek something I hope will be "great", or given up the "great work" path to seek something I know will be lucrative.
To bring this back into the lens of the article, I do think that for people who are not already financially independent, this can / should / is just one more constraint in the search through this space of "what should I work on". Some "great work" is lucrative while a lot is not. Financially independent people have the privilege to choose freely among the two kinds, while the rest of us have to focus on the lucrative kind to at least some degree.