Either party could adopt the position of the other party.
In some cases, the FASB and IASB may jointly undertake projects to improve both of their positions.
There is a tendency for the outcome to lean more in the direction of IASB positions.
It is not likely that the FASB will go away; it will find a reason to continue to exist.
The current situation is comparable to what the AICPA went through, when standard setting was shifted to the FASB.