Good summary here from Macelevey’s "Shiphandling for the Mariner"
This book is from 1983. That was almost 4 decades ago but the points made still hold. Now more then ever. In the last twenty years or so ship traffic has increased four-fold. That means back in the day where there used to be one ship now there are four.
Also sat comms and email means clerical work can be cheaply shifted from ashore to the ship and the dayworking chief mate has mostly been eliminated meaning higher shipboard workload and less assistance available for on-the-job training.