When Speed was added in 5th edition, the ability was tangential and never referenced by Kindred adjustment tables.
It gained more importance in 7th edition, when it became a part of the formula for combat Adds. But even then, all Kindreds got a ×1 multiplier for Speed: It wasn't considered something that varied from one Kindred to another.
There's no reason you can't make your own Kindreds (or variants of the existing Kindreds) with different multipliers for Speed, though.
Yes, I always thought that was an odd choice. I'd expect that a kindred based on cats, for example, would be generally faster to react than one based on bears. But it's his rule system; he can decide how he wants it to be. And we can change it for our own games, as gaptooth points out.
Speed seems to have evolved from a straightforward measure of running speed (Naked Doom saw the first introduction of speed, then Arena of Khazan re-introduced it, and introduced TARO for attributes) to also reflect reaction speed and agility, as with 7e it started to affect combat adds.
That's how I interpret it now. Not to have kindred adjustments doesn't seem right, but it is one less thing to have to work on and balance. If you give a + speed adjustment it shifts the power further away from the Human X1 default.
Perhaps a speed reduction is the way we could adjust Dwarves - their manual dexterity is not in question, but their speed? I know, very dangerous over short distances