The question has examples of the categories of reasons: policy-making, insufficient resources, specialists, education, non-use of standards.
These categories illustrate the constituents of the whole clinical care process, which isn't restricted to just the patient-medic interaction.
Based on the experience of numerous visits to my local National Health Service (NHS) hospital with my elderly father, I can describe the various parts of the service one meets.
A patient being brought into A&E (Accident and Emergency) at an NHS hospital for example will be met by a triage nurse, then a porter to move the patient to the bed in the A&E, nurses to move the patient onto the bed, then a phlebotomist to collect a blood sample, A&E doctor to assess and, after being admitted to a ward, the ward nurses, pharmacists, specialists or even registrars.
Each of these groups of people may be considered at a different level with the whole healthcare organisation. The use of the term different-level may then allow the distinction of these separate groups of people.