I have a suspicion Paul Allen and the Vulcans are going to hold the city's feet to the fire on this one. When the team was (supposedly) struggling financially, the city refused to re-negotiate the contract. Paul can be vindictive when he thinks someone screwed him over (just ask Kevin Pritchard and Rich Cho).
The only good news is Allen owns the Rose Garden. So, he likely doesn't want to see it vacant. Still, if the city doesn't capitulate, he may just say fuck you, move the team and tell the people of Portland he hopes they enjoy multiple engagements of Disney on Ice.
BNM