Final answer:
The principal HIT component failure in the scenario is related to usability, which indicates the system is not user-friendly or conducive to the physicians' workflow.
Step-by-step explanation:
The failure in the scenario provided is primarily related to the usability of the new health information technology (HIT) system. Usability refers to the ease with which the users can learn to operate, prepare inputs for, and interpret the outputs of a system or component. When physicians find the system too time-consuming or challenging to integrate into their typical workflow, resulting in them not using the HIT system as intended, it is a clear indication that the usability of the system needs improvement. Adequate usability is essential for ensuring that health care professionals can efficiently and effectively interact with HIT systems, which otherwise could lead to resistance in adoption and potential failure to realize the expected improvements in health care and efficiency.