The two cases, though faintly analogous, are very different in a relevant way. The theory of evolution was invented to solve a problem, the problem of Design, as epitomised in the Argument from Design, namely, how could the adaptations of living organisms come into existence without design. (See William Paley's brilliant version of the Argument from Design, which Darwin refuted with his theory.) A proposed mechanism that started from designed precursors would not solve that problem. Hence the Theory of Evolution has to include the assertion that the first replicators formed, without design, from un-designed precursors.

There is no equivalent problem in the case of star formation.

Moreover the 'origin' process does constitute perfectly ordinary Darwinian evolution under the standard definition, because those first replicators were formed by variation, followed by natural selection, starting with a population of non-replicator precursors.