Tar Sands and water, jobs

Debate over the State Dept’s EIS: EPA says draft report “insufficient,” though not willing to criticize outright. Others not so shy:
Bill McKibben points out that the “jobs” argument in favor of pipeline doesn’t hold water, as it were. Further, the pipeline is only designed to last 50 years, and most of its oil will be shipped overseas:
My question: why not invest millions in crumbling, vital infrastructure (such as water pipelines, aqueducts, dams, levees, and locks) that will benefit the nation, instead of oil pipeline that will benefit a few (Canadians) and pose a threat to water supplies?