Beyond Predictive Monotony: A Double Machine Learning Approach to Causal Synergy and the Digital-Distance Paradox in Tourism

Although digital footprints are widely used to forecast demand in tourism, the causal mechanisms by which "born-digital" mega-monuments influence the sustainability of legacy heritage ecosystems remain underexplored. Addressing the issues of "Methodological Monotony" and "Endogeneity Blind Spot" identified in recent literature, this study employs a Double Machine Learning framework to isolate the causal synergy between the Statue of Unity in India and a network of ancient UNESCO heritage sites. Utilizing optimized ensemble learners, we identify a robust "Anchor Effect" for proximal sites and a striking ‘Digital-Distance Paradox" for peripheral nodes.Causal mediation analysis reveals that 76.5% of the synergy of distal destinations is digitally mediated, positioning the modern monument as an Informational Catalyst that reduces search costs and bridges geographic barriers to cultural participation. We propose a Dual-Track Governance framework to mitigate the "Digital Displacement" and ensure the equitable preservation of regional destination competitiveness within the "Algorithmic Gaze". The study provides an empirical bridge between Information Foraging Theory and modern econometrics, offering a scalable framework for heritage site co-opetition in the tourism 4.0 era.