Actually they so see it, but if you have been doing it for years they don't see it as something they should do. If you really want them to change then you have to change as well and stop picking up after them. My motto is if you made the mess then you clean it up. If we make the mess together then we both clean it up. Tell them we all live here and I am not responsible for everything and everybody. It does take a bit of patience but it does work eventually. Be prepared for resistance.
Ask the children if you make a mess at school who cleans it up not the teacher. If the teacher assigns homework and they don't do it are there consequences. I bet there are. So enforce some consequences. As for you husband same thing. Does his boss clean up after him. If he's asked to do something can he just play stupid or step over it. I bet that wouldn't fly with his boss.
Hey and I bet you work outside the home as well,and even if you don't you need to call some shots and set some rules. Again expect resistance in the beginning, but if you don't do it (and you can stand the mess) and they learn to do it you have taught them some life lessons about living in the real world. But again use baby steps and it will take some changing on everyone part. Good Luck!