One way in which this tension been resolved (often to the consumer's detriment) is with MAP (minimum advertised pricing) agreements. Such agreements, as an example, permit Apple and other electronic stores such as Best Buy to peacefully co-exist in markets in which they both have presence. Both parties agree not to undercut the other, and both share the burdens and benefits of sales.

With respect to dealerships' monopoly on repair knowledge, at least one state (Massachusetts) has passed a "Right to Repair" act, and car makers have largely made it easier for independent mechanics to obtain service and diagnostic information, so this issue is basically moot now. See, e.g., http://en.wikipedia.org/wiki/Motor_Vehicle_Owners'_Right_to_...