Self-actualisation doesn't have much to do with being rich or not (riches might even be an impediment as much as being poor -- "slave to money", "golden handcuffs", etc.).
Besides, PG is not lecturing some third world sneaker factory workers. His audience is startup founders and/or developers, that, as a rule, don't live "hand to mouth".
And the particular advice (whether right or wrong) applies to all income levels. Even if you're a starving artist It can be good to "copy what you genuinely like" as a way to progress (artistically, if not financially).