Is the Waiting Room Necessary?

I spent 40 minutes waiting to begin diagnostic tests preparatory to seeing my ophthalmologist. What a waste of my valuable time! And my calculations from data from the American Time Use Survey suggest that this is a standard problem: the average adult American spends four hours per year waiting for medical or dental care, with each wait averaging around 45 minutes.
Pricing this time out at even half the average wage rate, the cost amounts to about $5 billion per year. Seems like a lot, and very inefficient, but what is the alternative?
The only way that every medical provider could ensure no waiting would be for the provider to have downtime herself, in order to have unutilized resources, both of her time and the services of the capital stock used in the practice. I’m not sure what’s the right mix of provider and customer waiting; but as annoying as my waiting is, the current system may be economically efficient.