QGD / MPDT and String Theory: Achievements, Structural Challenges, and a Minimal Axiomatic Alternative

String theory is the most technically sophisticated attempt in the history of physics to construct a unified, UV-finite theory of all fundamental interactions. Its achievements are genuine: it is the first known framework that includes a consistent quantum description of gravity, it derives general relativity as an output rather than an input, it generates hints of a unified particle spectrum from a single object, and its mathematical productivity — from mirror symmetry to the AdS/CFT correspondence — has reshaped large areas of mathematics and theoretical physics. This paper evaluates string theory against the Minimally Physically Derivable Theories (MPDT) metatheory, with full acknowledgment of these achievements, and argues that the framework's deepest failures — the landscape of 10⁵⁰⁰ vacua, the requirement for extra dimensions, the non-observability of supersymmetry, and the composite character of the string — are not technical obstacles awaiting a better compactification scheme or a stronger selection principle. They are structural consequences of a single foundational decision: extending the fundamental constituent into a continuous one-dimensional object propagating on a continuous worldsheet. That decision was taken to achieve UV finiteness. The Quantum-Geometry Dynamics (QGD) framework, derived within the MPDT programme, achieves UV finiteness without that decision — not by extending the constituent but by making discreteness axiomatic. The result is a framework with no landscape, exactly three derived spatial dimensions, no supersymmetry requirement, and a single indivisible point constituent from which all particle species emerge as composite preonic structures. String theory's achievements survive within QGD as effective approximations; its structural failures dissolve without replacement. The paper works through the comparison systematically: a self-contained presentation of the two QGD axioms and how each structural wall dissolves under them, a translation dictionary between string-theoretic and QGD concepts, a discussion of where string theory's achievements survive as effective descriptions (including why the graviton's spin-2 mode still appears and how AdS/CFT reflects boundary preon dynamics), and a set of differential predictions — beginning with the absence of superpartners at any energy scale — that distinguish the two frameworks empirically. String theory's UV-finiteness achievement is also given a direct portfolio grounding: the Preonic Truncation Theorem shows every integral in QGD is already a finite Riemann sum truncating at the preonic precision bound, as a direct consequence of the framework's first axiom rather than a regulator introduced to control an otherwise-divergent continuum calculation.