Glendale wanted the 10-15 year lease because they wanted stability and certainty. ESPECIALLY considering that all of the rhetoric from the Ice Clowns, the NHL, and immediately after buying the team Meruelo joined in, that Glendale was not the long-term solution for the team. In other words, it was obvious that the team was angling to leave. Glendale's offer was, "Sign long term here, and we can figure out something that works for all of us. Otherwise, get lost."
I am fully convinced that if the team had signed that lease, Glendale would have responded with all sorts of breaks, subsidies, what have you to be the quid pro quo for the commitment.