To complement @Dagon’s comment, another difficulty is that Skepticism itself is also a philosophical model, which can be taken either as merely epistemological, or as a metaphysical model unto itself, so the initial 1:1 model actually giving Skepticism a 50% prior vs. all other models. And then we have some relatively weird models such as Nominalism, which is metaphysically skeptical except for affirming, atop a sea of complete no-rules free-formness, the absolute will of an absolute god who decides everything just because.
Fun detail: my Philosophy major followed a method called “monographic structuralism” that consists in learning each philosopher’s system as if we were devout followers of theirs (for the class duration). The idea was that before opining on this or that philosophical problem it was worth knowing that philosopher’s arguments and reasoning as well as they themselves did. So one studied philosopher A enough to argue perfectly for his ideas, finding them perfectly self-consistent from beginning to end and from top to bottom; then studied philosopher B similarly; then philosopher C, ditto; and so on and so forth, which invariably led one to learn two philosophers who said the exact opposite of each other while still being perfectly self-consistent—at which point one threw their hands up and concluded the issue to be strictly undecidable. In the end most students, or at least those who stuck with the major long enough, became philosophical skeptics. :-)
To complement @Dagon’s comment, another difficulty is that Skepticism itself is also a philosophical model, which can be taken either as merely epistemological, or as a metaphysical model unto itself, so the initial 1:1 model actually giving Skepticism a 50% prior vs. all other models. And then we have some relatively weird models such as Nominalism, which is metaphysically skeptical except for affirming, atop a sea of complete no-rules free-formness, the absolute will of an absolute god who decides everything just because.
Fun detail: my Philosophy major followed a method called “monographic structuralism” that consists in learning each philosopher’s system as if we were devout followers of theirs (for the class duration). The idea was that before opining on this or that philosophical problem it was worth knowing that philosopher’s arguments and reasoning as well as they themselves did. So one studied philosopher A enough to argue perfectly for his ideas, finding them perfectly self-consistent from beginning to end and from top to bottom; then studied philosopher B similarly; then philosopher C, ditto; and so on and so forth, which invariably led one to learn two philosophers who said the exact opposite of each other while still being perfectly self-consistent—at which point one threw their hands up and concluded the issue to be strictly undecidable. In the end most students, or at least those who stuck with the major long enough, became philosophical skeptics. :-)