Whereas some of the new and innovative practices gradually diffuse and become fully institutionalized, most others either become rejected early or only reach an established position practices alongside others. However, neither the distinctive characteristics of the diffusion processes that lead to the latter outcome nor the reasons that prevent widely diffused and established practices from becoming taken for granted have received systematic attention. To fill this gap, we examine how the diffusion of the practice of alliancing and the respective field-level discourse were intertwined in the field of infrastructure construction in Finland, 2009-2022. Our analysis yields a conceptual model that explicates how and why an initially groundbreaking practice is prevented from becoming fully institutionalized in its field. In its entirety, the study encourages differentiating between those diffusion processes that continue until semi-institutionalization and those that result in a full institutionalization of a practice.