Xanathar knows many things, some might say “Everything” would he know how to bridge the gap between Abeir and Toril? If so, how? Yes, but he also knows the risk (costs vs. benefits), and would be highly reluctant to do so. Right now, he has other, nearer fish to fry. (Which fish, exactly? NDA!)
— Ed Greenwood (@TheEdVerse) January 26, 2018