With all due respect, I feel like this kind of thinking is a bit myopic.
First, if any of the O's would benefit from sight testers it would be the opticians in the U.S. who have long lobbied to be able to do refractions and contact lens evaluations so that they can sell glasses and contacts from their own optical shops. A good friend of mine lives in Vancouver, BC and has a great practice downtown. He has fought this sight tester issue with their government since it first came up. They have made some headway, but it is very possible that something like this could come to the U.S. if we are not careful and do not keep the public informed.
Second, to lump all retailers together and say they are only about hawking their wares misinforms where some retailers are going. Luxottica is one who is moving hard and fast into new areas where most on this board have not thought to go. See this article to get a little idea of what I am talking about:
http://www.luxottica.com/en/tools/eye-hub-australia.html
I am all for private optometry succeeding in the future, as I am one of them. However, we cannot bury our collective heads in the sand and believe that we will always be the "quality" provider. Where there is big money, there are big ideas that can lead to new ways of thinking.
Does this bother me as a private practitioner? Nope. Competition is good for all of us. It keeps us on our toes and makes us stretch out of our comfort zone to be the best we can be for our patients.