Old rumor he brings up when it seems relevant. Maybe Wicked was thrown out as a possible replacement a decade ago during a meeting once, but no new information has come out recently regarding it.
Or, as
@Joe puts it:
Edit: And I listened to the episode. He didn’t say he believed an agreement was in place, he believed an agreement could be made. Very different things. Don’t expect Universal to give up the Marvel rights, ever.
Double Edit:
Yes, this: