I’m no lawyer, but it seems to me if they built the building, and maintained it, then they are due money from the city. I’m sure there are plenty of good lawyers who would put the city through hell.
"On May 31, the City Council voted 16-to-1 to authorize ending the lease, though Mr. Clarke and other Council members continued trying to negotiate a settlement. Those efforts ended this week, Mr. Clarke said, adding that he had shifted his energy toward trying to see if there was a way the city could reimburse the group for improvements it had made to the property over the years. Boy Scout officials said they do not have a cost estimate for the improvements, but Mr. Jubelirer said it would exceed $5 million."
In some places if you reside there for decades and make significant improvements to the property, it is yours.
Now granted there was a lease agreement for the land but the building is still an “improvement” and has been maintained.