You can have a checklist item for threats...it is a choice by those who run the airline.
When I taught flying, I explained what had to be done on taking the runway for takeoff...checking final for traffic was one of them
checking the compass/dg/heading indicator was something also part of the training.
IF pilots are checking things because it is a part of their training, the checklist might be shorter.
Who really forked up? Look at the training department for the real answer...and both pilots first instructors.