"You, the founders, should only build a product and talk to customers; everything else is superfluous and a waste of time."

I found it interesting that this seems to be described as bad advice that boxes founders in.

"Hiring is waste of time, paid advertising is waste of time, content is waste of time, talking to investors is waste of time, getting media coverage is waste of time."

The above all seem to be like a waste of time—but the OP is claiming otherwise. Perhaps this speaks to some YC companies being more mature than they used to be when they enter a cohort?