I think the ability to call in installations was planned, but scrapped/not implemented, given it's inclusion in the off map support menu.

While I do want to be able to change fits if the Supply Depots on the field are destroyed, which often means either dying or a very long and slow trek back to ground base, I'm not sure that a portable Depot is the way to solve that. Fortifying an objective with Nanohives is already common, so non-Triage Hives would simply be replaced with Depot Hives, still replenishing ammo but also allowing quick swaps to and from Logi or Heavy as needed to defend against any push.

There's also the fact that a Depot Hive would the equivalent of CoD's One Man Army perk; Fit all non-Sentinel loadouts with a Depot Hive and you can, effectively, swap fits on the fly in virtually any situation. Nanohives become obsolete as you get all your ammo, and equipment, back when you switch fits. Rooftop campers armed with MDs and PLCs would have a field day, since the Depot Hive would better than a Nanohive, since Depot Hives would be self replenishing when you swap fits and it would give them all their ammo near instantly.