Smileless, I am sure that you are right in what you say about it being difficult and exhausting to look after GC.
I am not yet at the GC stage with my semi estranged daughter but, as they live 100s of miles away (they have told me which county but not the address!), I don't suppose I would see them much anyway. But I think I'm ok with that, as I wouldn't want to provide childcare - apart from it being tiring and a huge commitment, it is too much responsibility and can be the source of arguments and resentment, if the threads on Mumsnet are anything to go by. There are threads everyday saying how much the DILs hate their MILs, and complaining how they are not following out their instructions to the letter when looking after the GC. Then there are those who are resentful because the GPs aren't doing enough, dare to have a life of their own etc.
I suppose that if you have already bonded with a GC, it is different, and desperately sad to be cut off from them, but it's all academic for me, at the moment. I suspect that I am trying to persuade myself, in order to be prepared and minimise the pain.
Anyway, on a more positive note, DH received a nice Father's Day card from her yesterday, which has cheered us. She still doesn't answer the phone or text messages, though - not that I send them very often, as I don't want her to feel pressurised, and also it make me feel sad and rejected when she doesn't reply.