Did it just happen that Makuta sent the rahkshi to receive it at the same time Takua found it? So what would happen if Takua never found the mask?
He sent them because the mask was found.
The universe would just suddenly explode!
He found out that they found the Mask, and went "Uh oh, that's not good. Time to bring out the big guns!"
I remember reading in makuta's guide to the universe that that was the one thing he did not expect he was like "Oh crap, well I don't want to kill the toa nuva, but that Takua guy needs to die"
Makuta would have won, the end.
After a long chain of events, the Avohkii and the Kraahkan would have fused, creating a world without light or darkness, i.e. the Matoran universe would have become part of the Twighlight Zone. A crossover I'm willing to see.
The Turaga would have to "stumble upon it" and make it like Ninjago where they test everone to see who is worthy by giving them the mask and seeing if it shines