"I know Hacker News types think that’s a great list of niches, but it’s actually a really terrible one. You can’t sell to ANY of those people."
Even as a conversation between two people it's ambiguous what the "you" means, in spoken english it would be distinguished by emphasis.
For example "YOU can’t sell to any of those people." would imply the speaker is referring specifically to the addressee, but "You can’t sell to ANY of those people." would imply a generic "you" referring to the general case of being able to sell to those people.
