I know this is somewhat of a false dichotomy, but at some point I think PG's essays started to shift from being directed at startup founders to giving advice to his children that they can read when they grow older.
That said, I think there's more of a zeitgeist change than actual change in pg's content. Things sound different 10-15 years apart. A lot of things age poorly, often: idealism, stand up comedy... most anything avante garde-ish.
Clever people spoke highly of agile,for example, when it was manifestos and such circa 2005.
But the person you're correcting seems to have already noticed that, and has corrected themselves.
Not that that is necessarily bad per se, there can be a lot lot of value to reminding people of things that may seem obvious. But it's annoying when people treat him like a genius for saying fairly standard platitudes in a clever way