With over 65 facilities fully converted in the US and over 13,000 fuel cell units in service, I think it's fair to say it has started.

As someone else in this thread mentioned, any battery, even Li-ion, will alway require long recharging times and for multi-shift Distribution centers this downtime costs money in terms of productivity. Sure you could add fast chargers and get this down to 20-30 minutes but that still is a lot longer then 2-3 minutes for a hydrogen fuel cell. Not to mention the peak demand electric charges that would result.