I think there is some truth to that. Loki is very much my dog, but he loves my husband too. He also loves my mom, brother and my husband's sister. He is more expressive about everything so I know if he's scared, happy, hungry, etc. He knows how to specifically ask for what he wants (water, food, a lap, outside) rather than Sammy who just barks and runs in circles
He and I did obedience training and he is very well trained. Right now Loki is napping next to me while Sammy is running around the house being crazy.
Sammy is the happiest dog on the planet so she loves to see everyone, but in a more excited rather than affectionate way. She does snuggle a lot, but it's always on her terms. She loves us, follows us around, always needs to see what's going on. So it's not that she's not affectionate, she just entertains herself and she's less needy than Loki. Loki runs to me when something happens and Sammy runs to investigate. She definitely thinks she is in charge and can't really be bothered to learn silly things like commands or how to follow rules
Sammy makes me laugh and Loki is my buddy. Does that make sense?