Honestly I didn't think it was well put at all. A vast number of words for very little content, and what content can be distilled is useful to approximately nobody. I've never known a person who needed this advice.
If you're exceptional in some niche you don't need the advice (if it can be called that). If you aren't, you can be your best and thrive if you are motivated, in which case this is similarly unhelpful. In the final case, if you aren't intrinsically motivated to do 'great work' then you won't.
I think part of the point of it is to assure people working on niche problems that embody some of the qualities of what pg is describing as great work. It’s easy to look at the shiny zeitgeist and feel a lot of self doubt if you’re off working on something few outside the niche seem to understand. I’m not sure if this an advice piece as much as an encouragement piece to those readers going through those trenches.
If you're exceptional in some niche you don't need the advice (if it can be called that). If you aren't, you can be your best and thrive if you are motivated, in which case this is similarly unhelpful. In the final case, if you aren't intrinsically motivated to do 'great work' then you won't.