I recall from 40 years ago when a Pacific island airline bought two new Boeing 737-200's directly from Boeing. A Boeing instructor pilot accompanied the first aircraft from USA to the island and jump seated on various routes to advise the crews where necessary. The chief pilot decided in the meantime to add several more items to the 737 start up checklist based upon his personal views of what should be included or double checked.
The Boeing instructor pilot pointed out that when Boeing designed the 737 as a two pilot aircraft (as against the 727 which required a flight engineer), some systems were automated in order to meet an airworthiness limitation to the number of switch movements and eye scan movements applicable for a two pilot operation. Violation of those limitations meant a flight engineer must be carried as a third person in the cockpit.
That point was wisely accepted by the chief pilot and the extra items deleted from the appropriate checklists. This two crew airworthiness principle seems to have been long forgotten, judging by the number of additional (need I add superfluous) call-out and checklist items foisted upon some airline crews by well-meaning, but historically misguided, chief pilots. Flying school operators are by far the worst offenders with unnecessarily lengthy and superfluous checklist items that often dismay and bewilder their student pilots. .