I'm sure this aesthetic relativism holds up under argument, but this is an 'anti realization' that:
-Reduces explanatory power (if Moby-Dick and 50 Shades are the same, why has one been lauded for 100 years, minted the careers of countless academics, etc.?)
-Makes the world less interesting
One of them has existed for more than 100 years. One of them has been granted credibility by a small number of academics before becoming a safe conservative choice for subsequent ones.
I don't know, but those sounds like some plausible answers.
On the first point, explanation is inherently subjective. It reduces explanatory power purely because you're forced to acknowledge it was never universally appropriate, which tracks. The variety of explanation you're referring to in this context is one that I always found to be unsatisfactory. It's inherently stripping context (IE every component of what makes something the right place, the right time) out of the equation, which makes comparative analysis absurd.
On the second point, I vehemently disagree, and I'm curious how you think a larger, more complicated world can be argued to be less interesting? Does the fact that your hallucinations and delusions are vacuous, and that they don't sit alone in a dark void, paralyze you with fear?