Digital health ecosystems may be the next revolution in improving citizens' well-being, health delivery, data management, and health system processes, but solutions have not yet been broadly established. Reasons could be that health service-organizations have misaligned interests or lack capabilities. This study investigates reasons from a multi-health-service-organization perspective, differentiating between payers, insurers, healthcare providers, and innovators, detailing the expected value-adds, preferred participation roles, and required capabilities including a rating assessment. Findings are based on a taxonomy development methodology, which combines a literature review with semi-structured qualitative expert interviews, conducted using a modified Delphi approach. Interviews were thematically analysed. In total, 21 experts across the four health service-organization groups were interviewed. The capability taxonomy includes a total of 16 capabilities, categorized in three themes: 'Health market', 'organizational', and 'technology and informatic'. Providers expect a value-add from strengthening their health process economics through efficiency gains but reveal the largest capability gaps, especially in 'interoperability' and 'platform'. Innovators' 'technology and informatic' capabilities complement well with those of payers for the 'health market'. We present a health service-organization-specific three-stage approach for establishing digital health ecosystems. Payers and insurers should address their 'technology and informatic' capability gaps, using technical enablers or forming new entities to reduce dependencies from legacy information technology systems. Innovators should clarify their monetization models and create positive awareness for their services, possibly entering the market directly. Providers must address interoperability issues and may require incentives to encourage their participation. Findings suggest governmental policymakers to prioritize three health policy initiatives.