(I think) His point is not that investing is a zero sum activity but that active trading basically is. For me to make money day trading someone needs to loose money. The total "growth of the pie" is a slow process that you capitalize on by buying and holding.
Fair enough! We do have quite a few users also running medium and longer-term focused strategies such as accumulations on dips
Yes, that is what I meant. Thank you for expressing it more clearly!