Identifying the scarce resource
Most definitions of economics stick pretty close to that of Lionel Robbins: -
The science which studies human behavior as a relationship between ends and scarce means which have alternative usesThe debate over how to best allocate finite resources amongst infinite demands is a commonplace and nowhere more so than in in the health care arena. We're all going to die of something so the expense of sickness will always outstrip funds available for cure.
Successful pharmaceutical marketing is the process of ensuring that the condition treated by your drug enjoys as high a priority as possible in the system in question; be it the WHO, the NHS, a Strategic Health Authority (SHA), a Hospital Trust or the patient cohort seen by the individual GP. The truth is that resources (time, money, beds) given over to HIV is a potential denial of diabetes treatment. HIV wins so diabetes loses. Or vice versa.
At an intellectual level we generally accept that quasi-objective measures like the QALY (quality adjusted life year) are necessary yet they seem wholly callous when applied to the treatment of people we love. Tabloid papers thrive on stories condemning the cruelty of the 'postcard lottery' which is just the shorthand for the situation whereby different parts of a country have different health priorities. For example, it is far better to get cancer in the southeast of England than west Scotland because Glasgow's cardiovascular issues are (still) a higher priority than cancer.
Doctors are trained to react subjectively (i.e. in the best interest of the individual patient) which often puts them in opposition to the objective needs of the system (NHS, SHA, Trust). Pharma selling exists in part to exploit this gap. This is not unethical per se; the representative is trying to promote the interests of the patient whose health needs will be best met by her drug. Win-win.
The scarce resource most important to the pharma company is not the drug budget (although this is of course vital), but rather the motivation of the individual doctor to fight for the individual patient / drug. Every day almost every doctor in Britain is faced with the prospect of having to fight for access to a treatment for a particular patient. Not every doctor takes up every patient's cause as it would be impossibly exhausting to do so.
Identifying which customer has the energy to take the fight to the system on your behalf is a vital task for any salesperson selling into a complex system, especially when that system uses inertia as a cost control mechanism.