It depends on your deployment scope and the level of integration with your existing systems.
PassKit technology via CherryPie, our API and Loopy Loyalty is ready today.
Typically what takes the time - especially with larger corporates - is securing management buy-in and sign off (depending on discretionary budget)
Deploying/training operations staff can also take a little time. Its important that "on the ground staff" know that smartphone content is accepted and what they need to do when a customer presents their Pass to take a real world action. The more branches or stores you want the Pass to be accepted at, the more time it may take.