whenever they can get a better discount

Hah, I wish. I'm a buyer for a major multinational corporation. Was part of an opportunity assessment on health insurance providers. We did our market survey, contacting third party consultants who were experts in the field, put our recommendations forward, and... the execs insisted on the most expensive, worst coverage offeror. Why? Because they're also a major client of ours, and they didn't want to risk the business relationship by switching providers. If it was just the best discount despite shit coverage? Fine, I get it, but reciprocal business turned out to be the only factor actually considered.