Contemporary AI-mediated platforms systematically narrow the conditions under which authentic agency can be expressed—a process Commentary terms stage compression, operating at two levels: synchronically, constraining the range of identities available in any given interaction; diachronically, foreclosing the developmental windows within which genuine identity exploration can unfold. Existing health psychology frameworks address downstream symptoms without theorising these structural conditions. This Commentary identifies this gap and sketches Dual Agency Theory for Authentic Being (DAT) as one possible direction: drawing on structuration theory, relational autonomy frameworks, and self-determination theory, DAT proposes that self-directed and other-directed agency are mutually constitutive. Platform success, on this account, should be measured not by engagement metrics but by whether users develop stronger capacities for self-regulation and genuine social connectedness.