Board Thread:Mortal Kombat (Alternate Timeline)/@comment-34018739-20190327152005/@comment-33695765-20190508183740

Past Kabal's speed could easily be explained as tech he got from future Kano.

As for why not everyone uses this could easily be explained as not having the right physical requirements (Kabal mentions in one of his intros that you need a strong heart to run fast) or the 'speed device' is temporary.