"If curb-side pickup becomes more popular they would increase available slots by allocating more resources. What is happening right now is you have one or two managing curb-side and a ton inside managing everyone else."

You're ignoring how it's a costly loss-leader for them. The pickers cost money. The storage space costs money with additions of new customers using the space designed for less until an expansion happens. One, little building might be in the six digits. The IT systems are probably older ones designed for lower volume. They have to integrate with all the other enterprise systems. There's a lot more going on in big companies scaling up than just add more people or slots.