This morning, I took a walk through Barnstable, Massachusetts, on Cape Cod. I’m here on a family vacation — a vacation that is taking place just 60 miles from our Boston home — because our state still has a 14-day quarantine for returning from out-of-state travel. The Cape Cod tourist economy is operating well under its normal end-of-June levels. The house we rented — normally booked all summer long — was unused until we rented it just before the July 4th…