While critical scholars and activists have made a case for the transition towards more sustainable and more equitable economies, this article shows why post-growth futures have proven notoriously elusive to date. A common explanation for this lack of progress is that growth-focused economic thinking, especially neoliberal but also conventional Keynesian ideas, is pervasive, adaptable and resilient. Combining the post-growth literature with key insights from the ethnography of infrastructure, I argue that we need to take seriously an oft-neglected obstacle to overcoming the pro-growth status quo: infrastructures of growth, which are material manifestations of economic practice. Infrastructures of growth may indeed be stickier than pro-growth ideas because the existence of certain types of infrastructure not only incentivises certain forms of behaviour but also continuously validates growth-oriented thinking. To illustrate this claim, I present evidence from the secondary literature on environmental regulation and the care economy. The main message of the paper is that to enact post-growth futures, ideational change must be complemented by parallel efforts to re-engineer the infrastructural foundations of contemporary economies.