I agree with him in principle; it’s better to use what others have made, than to reinvent (a slight variation of) the wheel. I personally believe that pg’s reasoning was mostly because it was just fun to make, and as someone as active in the startup ecosystem as him, making something new rather than using the status quo makes a lot of sense.
Regardless, I would have found it much more interesting if he gave some concrete examples, and/or focused on facts.
I also don’t know Erik Naggum that well, and I’m wondering if this quote is an accurate representation of his style.