Open this photo in gallery: Prime Minister Justin Trudeau and his wife, Sophie Grégoire Trudeau, are separating after 18 years of marriage. Mr. Trudeau and Ms. Grégoire Trudeau make their way to a government plane as they depart the airport, Sept. 16, 2022, in Ottawa.Adrian Wyld/The Canadian Press At what cost? Re “A lesson in the importance of raising productivity, from Down Under” (Editorial, Aug. 5): In 30 years, GDP per capita in both Canada and Australia has tripled. Where do we think this is going? When are countries like Australia and Canada, like all developed countries, going to realize...