Joined: 25 May 2006
Location: Luton, UK
They can't. You've missed the point of my post. Myst V is a part of the MO:UL timeline now. I suggest that you read up on this on the DRC site. It's the reason for Yeesha's appearance as a hologram both times at the end of the prime ages, for example.
If Cyan wanted to, they could simply go back and write in the stuff they wanted to happen they way they wanted it to happen, and ignore Myst V (they even established that Myst V was a GAME, and not to be taken literally).