Historically, string theory was the result of modeling amplitude scattering for hadronic physics, then discovering that it contains a spin-2 massless boson reminiscent of the graviton. Adding conformal conditions, General relativity and Yang Mills field equations can be recovered in a 10D universe, as a supersymmetric theory. This evolution implies that superstrings are derived from the bootstrap and string theory, and that, therefore, recent claims of range compatibilities between superstring results and gravitational bootstrap are actually expected and not the surprise, or divine sign of nature, that some have claimed. In fact pursuing the reasoning, also inspired from our multi-fold theory work, we conclude also that indeed superstrings is the only theory that satisfies sufficiently well-defined, essentially non perturbative, gravitational bootstrap. While this may sound like a resounding confirmation of string theory, we then discussed why it might not be so, but instead emphasize that conventional gravitons, susceptible to scattering modeled with S-matrices, simply do not exist in any other consistent theory of quantum gravity like QFT-based gravity, LQG, Causal set sand other reconstructive theories. In particular, this is confirmed in the Multi-fold theory. We take it as a hint that much of the challenges encountered in quantum gravity may come from gravitons not existing. As a result, we continue to argue string challenges to the physicality of superstrings, now also including the physicality of gravity.The paper introduces a few theorems on gravitational bootstraps and gravitons and a new notion of quasiparticles, when the theory is not non-perturbatively renormalizable.