Are dynamically undecidable systems ubiquitous?

Stephen Wolfram has maintained that almost any system whose behavior is not obviously simple is computationally universal and, consequently, its long term behavior is undecidable. Wolfram's tenet is a direct consequence of his Principle of Computational Equivalence (PCE). In this paper, I propose an independent argument for the ubiquity of computational universality and, as a consequence, dynamical undecidability as well. My argument does not presuppose PCE and, in essence, it is based on the recognition of two facts: (1) the existence of a strong structural similarity between the transition graphs of any two computational systems; (2) the mapping needed for computational universality is emulation, which is itself a quite weak structural mapping.