Yes and no. There is no "mandatory" finalization date if that is what you are asking.
But you have to understand this. The pilots and the mechanics (yes they worked for a long period of time without a contract) were not "visible" to the public or Wall street. What I mean by that is they were not the "face" of UPS or interacted with everyone outside of UPS.
So you have 3 factors involved in not carrying this out years and years.
1. UPS is not the only IBT union.
2. Continued negative news about the contract NOT being finalized can not be good for the stock price.
3. No way in hell the company wants 250,000 pissed-as-hell drivers out there interacting with the public!