Did not read article because opening “hook” question was stupid. Why 1 crane for 50 to 100 trucks? How many containners can a crane pick up per day to load on a truck (dunno, but more than 1). How many containers can a truck carry? 1.
That's the problem. One container per truck. One crane per 50 trucks. That is why we have over a hundred ships waiting to get into port. It takes time to move a truck out of the way and position the next one. Now you have trucks lined up at the cranes. Cranes only move at a certain speed.
The port bottleneck is at the crane. Increase the number of cranes, you lower the bottleneck.