Jay-Z shuts down a boulevard between City Hall and the Art Museum every Labor Day weekend. That choice is the whole argument. The Benjamin Franklin Parkway is not a parking lot or a fairground. It's a European-style civic boulevard lined with museums and cultural institutions — the kind of street that announces a city taking itself seriously. For two days every September, it becomes Made in America's main stage, and Philadelphia's skyline sits behind the headliners like the city dressed for the occasion. The Rocky steps are to your left. That is not incidental. The iconography is intentional: Jay-Z's claim on this specific piece of civic geography is what the …