Thin-Film Persistence without Closure as Stability: A Descriptive Account of Finite Observational Intervals

Thin films are conventionally described through equilibrium and stability vocabularies grounded in classical interface physics. This paper retains classical references such as the Young-Laplace relation and Marangoni elasticity while asking how spherical form remains describable during a finite observational interval in which collapse-related divergence is already present. The account does not introduce a named equilibrium state, stabilizing mechanism, or additional physical agency. Apparent endurance is treated instead as persistence within an interval: the film remains observable as form, while thinning, fluctuation growth, rupture-readiness, and related tendencies have not yet organized the observation as collapse. The contribution is a descriptive constraint: observed persistence may be described without converting unresolved divergence into completed stability.