This paper addresses the challenges in designing and provisioning digital services for public sector. The ongoing digitalization of public services calls for scalable models for ecosystem based collaborative service design. However, while digitalization of services has been studied extensively from technical and financial viewpoints, less focus has been devoted for the collaborative service design processes. In this paper, we present a critical analysis of an alternative approach to public sector driven ecosystem based service design. The analysis is based on a deductive review of earlier research on ecosystem based digital service design, and an inductive theory making based on a representative case study applying pre-commercial-procurement practices.