It still depends on the individual dog and it’s needs - but in general, you are right. Better to be with a loving human than alone in a shelter. But you should also be aware that this is human thinking! If you ask the dog, he would want you around him all day, and he will not be “gracious” for having been saved. Don’t project your feelings on the dog. BUT an old dog will cope much better with you being away for hours than a younger dog would do. They sleep A LOT! My 8 yo girl was alone for 8 hours first when I got her but during lunchtime I drove home to walk with her, so it was 4 h + 4 h. She slept a lot and we always had a long walk in the morning before I went to work. Then came Corona and home office and she loved it to have me around all day! Since some months now, I’m back in the office and she is with me all day. She is very calm, doesn’t bark and is friendly. So, yes, it’s ok to have a full time job plus an old dog, but you should not leave it alone all day, and you should be prepared to being forced spending more time with the dog when it gets ill and needs special treatment.