Amid mounting global challenges, start-ups are increasingly adopting resource-constrained innovation models such as frugal, inclusive, reverse, and constraint-driven entrepreneurship. This study conducts a systematic literature review and bibliometric analysis to explore the evolution and convergence of these models within entrepreneurial ecosystems. Based on 347 peer-reviewed studies (2000–2025), the research reveals how scarcity fosters bricolage, resilience, and accessible innovation, particularly in emerging markets. It identifies key intellectual clusters and thematic patterns shaped by institutional voids, grassroots innovation, and social entrepreneurship. Keyword analysis indicates a shift from foundational frameworks to digital and impact-oriented innovation, underpinned by diverse epistemological paradigms. Using Bibliometrix and VOSviewer, the article maps the intellectual landscape, co-citation networks, and thematic clusters. The findings underscore the strategic role of constraints in driving innovation and advocate for interdisciplinary approaches. Moreover, it highlights the rising contribution of Global South institutions in shaping inclusive innovation discourse and calls for deeper empirical integration and theoretical synthesis.