Kind of a nitpick, but Cronus (the father of the Greek gods) is a different figure to Chronos (the personifaction of time).
Aside from that, I like the idea of this, and I’ve actually put forth my own version of this but using Mata Nui as that figure. I also mention that some of the powers of the brothers are stolen from Mata Nui and sealed into the three legendary masks of creation, control, and alternate futures.
It could be that the Mask of Time was so powerful, compared to the others, that the brothers agreed to divide it into fragments (two per brother) and hide it away, so that it could not be used against one another.