“…Vice versa, if incumbents succeed over time in developing jointly new complementary assets through horizontal collaboration among themselves, downstream entrants are more likely to backwardly integrate (P6b). These propositions contribute to the handful of studies on the intertemporal dynamics of alliances (Lavie & Rosenkopf, ), alliance terminations (Asgari, Tandon, Singh, & Mitchell, ; Reuer & Zollo, ), and vertical integration decisions concerning “make‐or‐buy” choices (Jacobides, Knudsen, & Augier, ; Leiblein, Reuer, & Dalsace, ). Moreover, our theoretical insights resonate with Hannah and Eisenhardt () because these scholars examine cooperation and competition of entrepreneurial firms in nascent ecosystems (see also Moeen & Agarwal, ), whereas we look at the problem of incumbents facing an ecosystem in which a downstream entrant emerges as a platform leader.…”