I think the difference is you seem to be a busy woman. You have a demanding and tiring job. I don’t reckon you are lazy, I’d imagine you are knackered!
Charlotte and Mark have NO excuse. She doesn’t have an actual job (I say that as someone in the industry myself!!), the work that she does is NOT difficult or tiring. Mark also seems to have a good work life, typical mon-fri 40 hours a week, no travel time, etc. They have no worry about childcare, trying to make sure they have someone to get the kids or summer clubs are all booked up.
So really Charlotte and Mark have no reason to not pull their finger out and make the weans a decent meal. They also have lots of money and a well equipped kitchen.