I want to add, to clarify why situations where there is the possibility of pts actually can indeed 'come to that' as unhappy as that option is:
The issue for me is that if I have no one who offers to foster indefinitely or home the dog, I cannot take him -- and the only option is to pts for the owner. Younger dogs I can commit to as I always have people waiting for a dog up to about 6-7 -- but older than that, especially this old, an offer has to be there to take him, for me to ask for short term foster. I have no resources and no ability to hang on to such a dog myself given my own living arrangements (no garden, cats in the house, small house with three dogs already and no 'spare rooms' in which to put a dog). Hence: as a rescue I am always dependent on my network of fosters, transport people, etc. I can't commit to dogs that will end up having nowhere to go and no one to take them. I only take on what I can manage. Many other rescues, with property, kennels, even a garden, can more easily make those commitments and thus buy more time.