Feels like an overstatement to say that the only thing that matters is Product Market fit.
Product market fit is certainly necessary but its not sufficient. Actually building and supporting the product (which includes culture, hiring etc) better than the competition also counts. FB vs Myspace could be an example.
I think the point is: If you had no abilities, and only f*cked stuff up without outside help, but you had solid product market fit, that's the only thing that matters because everything else you can acquire (including funds to compensate for your shortcomings).
At first it does sound wrong, but as I think back to all successful people I've known, including the ones that I could not for the life of me figure out how they got more success than I (eg, grade school dropouts, alcoholics, etc), I _can_ see how they leveraged an insight about PMF to achieve many things that I've always wanted and never achieved for myself. Very enlightening, but still kinda sad, actually, lol.
Product-market-fit is also not everlasting. Especially in the tech industry, things change really fast and even if you achieve a strong fit 1 time, you need to adapt over time or you become irrelevant.
Product market fit is certainly necessary but its not sufficient. Actually building and supporting the product (which includes culture, hiring etc) better than the competition also counts. FB vs Myspace could be an example.