yes, because the game does not talk all that much about biology or mechanics, does it.
And if we want to use real world biology then either the question is a non-starter because most of the species do not exist, or we have to accept them as very closely related to humans to allow for the interbreeding.
So we are back to them having very similar capabilities to humans, which also is reflected in game by their attributes.
We can also turn this around and say what in the game supports them having drastically different capabilities when it comes to walk and run speed, or long and high jump.
You know..it really doesn't talk much about biology does it.
So acting like there is a biological justification for species' physical limitations is kinda nonsense isn't it?
And we do
not have to accept that there is biological similarity that allows interbreeding..unless you plan to go ahead and make a case that celestials, fiends, and dragons all share this similarity. As much as I hate it's overuse as a single source of power, magic does a great job of papering over these types of concerns.
As far as similar ability scores having any use in comparing creatures, I submit to you..
the Avatar of Death..
no attributes below an 8 or above a 16..
Must be basically a human..right? Let's look at the sheet.
60 ft move speed, 60 ft fly speed..
Darvision, truesight
Near total condition immunity, poison and necrotic immunity
Can move through objects and creatures
Uuuuummmm.. call me crazy, but these seem a little north of what I'd expect a real-world human to manage. Maybe it's just an exception.
Let's see what other creatures are in this range.
Amnizu, Autumn Eladrin, Barghest, Battleforce Angel, Beholder..Blink Dog..
Uhhh..are we sure this is a good case to make even from a game statistics perspective?