You won’t hear Mark Zuckerberg say it this week when being grilled by the EU, but the social network’s entire business structure is dependent on a monopolized, self-regulated ad ecosystem. — During Mark Zuckerberg’s testimony to congress last month, Sen. Lindsey Graham (R-SC) asked him if Facebook had a monopoly — “Put it this way,” he said, “if I buy a Ford and I don’t like it — I can buy a Chevy. …