Fear of Intervention in End of Life Care Decisions

Are there questions no individual acting out of self interest can get to a “most correct answer?”  In healthcare, there seems to be a perception that a centralized health system will make poor end of life decisions.  I think about this and I think about nature.  I know dogs will try to wander off from a pack to die.  I also know we as a people who presumably care deeply about our dogs, take great care of them often providing them with a level of care that would leave most of the world appalled.  So for a thinking exercise, lets look at the dog situation from a few different angles to measure outcomes.
If one take the approach of minimizing pain, I think we choose to prevent pain far better than the dog would because the dog doesn’t have the knowledge base from which to base an appraisal of all outcomes.  If I look at length of life considerations, having already made the assumption the pain will be treated, I suspect the dog may want go on a bit longer than some of us are willing to permit.  Without pain or consequences of actions like incontinence, I think our 13 year old dog would sit in bed all day, happy with a head scratch or ten.  He may live for 10 more years.  Are people justified at some point saying it’s not enough of a life for their dog to sit here in a virtual coma?
Now on what basis do we make this decision?  Surely, it’s not in the dog’s best interest.  We’re killing him/her.  Is it a question of what is right for the family as a whole, to not spend thousands a year treating a dog and the bed and … for the sake of having a tail wag and a sympathetic look?  Now what if that money, effort, and time spent caring for the old dog could be spent raising puppies or taking care of an elderly neighbor’s dog?  Do the opportunity costs matter?  From the perspective of the family or the neighbor, I think we will eventually end up at a different end point than if we simply stick with the perception of the dog.
Now I know many would bristle at the comparison of elder care to dog care.  I use the point not to say they are the same but rather in an effort to try and create a framework for answering the question of whether choices should be made at any level limiting the amount of effort we are willing to put forth to save a life.  If the answer is yes, then we can go back to the dog example to look at how we came to assign a value for one more day of the dog’s life in an effort to create a starting logical framework for evaluating our own end of life choices.  Now, who gets to assign the value?  Is it the dog during the pain treatment regimen who won’t feel the pain, either physical or financial, or is it possible some outside decision maker may do a better job?  Is it the patient who wants the $50k per day treatment shown to increase the average life expectancy by three weeks or an outside decision maker who is in the best position to make a good choice? 
If one believes the outside decision maker is best equipped to decide, then the question comes down to whom we pick and on what basis.  Do we pick industry whom we expect to maximize profit or a government run bureaucracy with all its perils and inefficiencies? 
I relate a lot of my end of life care questions back to dogs, because I get frustrated that we can put an elderly, very sick, or hurt dog down, but euthanasia is against the law in much of the U.S., and few people ever consider the questions linked.   I get tired because we pay lip service to life without ever asking what makes it valuable.  At least when we take some of the “humanity” out of the argument, I can see some broader frame works immerge to possibly determine what can give life a value.