I'd actually argue the opposite. With states of matter, we're attempting to delineate how reality groups together sets of related properties that vary between conditions in similar ways for different substances.
Looking for the edges that nature drew.

With species though, we drew the lines. We drew them with a mind towards ensuring it's objectively measurable but it's still not a natural delineation. Taxonomists (biologists are actually a different field) mostly run into uncertainty with debating which categorization property takes precedence, and what observations of species have actually been made.
So while they debate which system to use, the particulars of the systems are pretty concrete.