While I've seen references to Bishop Iker's reversal on this matter, I'm not sure if there has ever been much detail given on exactly what happened. The timing of the Fort Worth petition suggests that things were going on behind the scenes: Jeffrey Steenson resigned as Episcopal Bishop of the Rio Grande in 2007 and went to Rome under the sponsorship of Cardinal Law. In light of subsequent events, this was clearly a key development, and the 2007 TAC Portsmouth Petition was much less important. In 2008, we see the Episcopal Diocese of Fort Worth petition to Bishop Vann. In 2009, we see Anglicanorum coetibus.
At some point in this timeline, Bishop Iker reversed himself on any intent he may have had to lead his Episcopal diocese in a body to Rome. (I will be most grateful to anyone who can provide specific references and links covering what happened and when.)
Since Steenson was already in Rome by the time the Fort Worth Episcopal clergy made their petition, since Steenson was previously a priest in that diocese, and since Charles Hough III was a prominent member of the petitioning group, it's hard to avoid the surmise that Steenson was somehow involved in the petition, and extensive back-channel communications were taking place. How involved was Iker in the discussions? To what extent were the Fort Worth clergy being made aware of the forthcoming apostolic constitution?
If Iker had brought his diocese into a proposed ordinariate, what would his role have been relative to Steenson? Steenson, we can be pretty sure, had the inside track to become US Ordinary. But Iker would have been the more senior and more prominent US Episcopal bishop.
Could some disagreement on this issue have prompted Iker's reversal? Certainly if the Episcopal Diocese of Fort Worth had entered the Catholic Church in a body, which was clearly a move envisioned in 2008, it would have been a much more encouraging development than what actually took place.