It is possible to discuss the business cycle without conventional aggregate analyses that focus on aggregate demand. I am particularly impressed with Arnold Kling's approach via Patterns of Sustainable Specialization and Trade (PSST).
But it is not possible to have the discussion without a public choice model. Politics cannot be assumed away. My favorite public choice model is Bruce Yandle's Bootleggers and Baptists. It is always about building and sustaining coalitions. Include at least one of these: For the children. For the poor. For the planet. There are many others.
Wendell Cox notes that the rhetoric on behalf of public transit subsidies for "the poor" leaves out much of the story. Poor people prefer used cars and get access to them when they can.
It's an old story. If there are going to be subsidies, send them to the demanders, not to the suppliers.