A robot dog will never teach you responsibility. If you forget to "feed" it, no big deal. Just plug it in later, when you remember. Forgot to walk it? Who cares? It's not like it makes a mess in the house. It won't need washing or brushing (unless it has fake fur), and you won't ever need to check it for fleas and ticks. It won't chew your shoes, bark all night or anything like that, which is good, but a pet that you can switch off, put away in a cupboard and forget about for a month or two is not a pet. It's a toy, and will always be a toy until it comes with crippling inconveniences. That, in a very real and practical way, is the meaning of responsibility: having to trade off your own happiness and convenience for the well-being of a person or creature that depends on you. When that need is designed not to outweigh your own wants (as in the case of a robot dog) then you are not responsible for it any more than you are responsible for keeping your TV plugged in.
Mokalus of Borg
PS - We've pretty much built our modern society on greater convenience.
PPS - And that means we don't know responsibility any more.