Yes the Uber/Lyft folks can only pick up and drop out at the Check-in building area which includes the Outpost bus stop. Nowadays, they have to come in the front and go past the guard. This is how the taxi and town car services are treated as well.
Disney's own Minnie Van is the only ride service permitted to pick up and drop off right at your campsite or cabin. They've reserved that strategic advantage for themselves (when they're running).
I don't know if Disney would allow others to pick you up at the campsite since MV won't be running. Might be worth asking when you check in.
Bama Ed