I know where you're coming from and mostly agree with you.
But... As a society, we've decided that there is a certain amount we will pay to cover health care and the public good.
As a society, we're apparently willing to perform ~3500 mammograms to save one breast cancer. (http://www.ncbi.nlm.nih.gov/pubmed/22358016) (I recall that the public is willing to spend $1 million per life saved, which is in the same order of magnitude.) From that standpoint, putting one AED in high-traffic public areas where they can possibly save a life isn't too unreasonable, given the price drops in AEDs in the last 5-10 years.
I agree that people need to be trained in using them, as well as BLS training. But more groups are doing BLS training, and one BLS trained person per hundred population would do a world of good. Last year my wife performed BLS at a department store and stabilized someone until EMS arrived. (The store manager mailed her a thank you letter and gave her a gift certificate.) A couple years ago I performed BLS on the street when someone rang the door of the place I was visiting and said someone collapsed outside.