If existence is the metaphysical primary, then all things which have existence must possess EQUAL existence qua existence. And these things which equally exist are either absolutely exclusive of each other, each possessing its own UTTER existence, in which case there can be no shared existence, in which case the existence of each thing is its own infinite singularity, making it impossible to define those things which are said to exist, because there are no relative relationships possible by which one thing can be defined as “this” which is not “that”, which is how anything is known and has meaning and relevancy; or they share a root existence which fundamentally, at its most basic essence, is all encompassing, and in equal absolute measure, in which case the existence of each object is merely a function of a singular, infinite existence, making it impossible to define those things which are said to exist, because there are no relative relationships possible.

More concisely: Relativity is absolutely necessary to define those things which are said to exist, and existence as a metaphysical primary is incompatible with relativity.