V78: The Environmental Axis Hypothesis — Dark Matter Profile Diversity as Cumulative Activity History, Not Particle Species

The proliferation of dark matter (DM) particle candidates — CDM, SIDM, WDM, FDM — reflects attempts to resolve scale-dependent successes and failures of the standard paradigm. We propose an alternative interpretation: the Environmental Axis Hypothesis. Rather than attributing DM profile diversity to particle properties, we argue that the inner slope α of DM halos is primarily determined by cumulative environmental activity history. We define an Activity proxy combining surface brightness, gas fraction, and rotation velocity, and demonstrate that: Low cumulative activity → core-like profiles (α > −0.5) High cumulative activity → cuspy profiles (α < −0.8) The apparent "CDM failures" at dwarf scales are not failures but expected outcomes of low-activity environments This framework predicts that the same CDM particle can produce both cores and cusps depending on environmental history, eliminating the need for particle zoo expansion. We present four explicit falsification conditions and identify key observational tests. The hypothesis reframes the "core-cusp problem" as an environmental memory problem: space records its cumulative activity, and DM profiles are the readout.