Unpacking Value Creation Mechanisms in User-Pay PPP Infrastructure Projects: An Integrated Grounded Theory, Fuzzy-DEMATEL and ISM-MICMAC Approach

User-pay public–private partnership (PPP) infrastructure projects operate as socio-technical systems in which institutional conditions, project viability, contractual governance, and stakeholder behaviour jointly determine whether service value can be converted into sustainable operating revenue. However, existing research often treats these elements as isolated success factors rather than as an interdependent value creation system. This study develops a systemic framework for explaining value creation in user-pay PPP projects by integrating grounded theory, fuzzy Decision-Making Trial and Evaluation Laboratory (Fuzzy-DEMATEL), and Interpretive Structural Modelling–Cross-Impact Matrix Multiplication Applied to Classification (ISM-MICMAC). Grounded theory identifies 23 categories and integrates them into collaborative foundation, collaborative process, and value realization. The subsequent Fuzzy-DEMATEL and ISM-MICMAC analyses focus on 18 factors within the first two dimensions to examine their influence relationships, relative importance, and hierarchical structure. The results show a six-layer mechanism in which socioeconomic and legal environments form foundational drivers, project viability factors occupy intermediate layers, and concession governance and stakeholder collaboration transmit upstream conditions toward value realization. User willingness to pay exhibits the highest centrality, while stakeholder value co-creation willingness constitutes the most proximate behavioural condition. The findings recast user-pay PPP value creation as a layered socio-technical system and identify where interventions should target institutional enabling, project viability, governance design, and collaborative behaviour.