Tbh, DS isn't much of a crier. He's quite a good baby.
I think some posters are possibly thinking about our situation in a different context than our reality actually is.
Having a baby and a teen in the house is a bit of a juggling act, but I think we've managed well.
Were up early, we take DD to school.
Then the day is generally ours for baby classes, swimming, groups etc and the housework I manage when DS sleeps.
I then collect DD. The afternoons are hers really.
The evenings I'm working, if DH is assumed to be home after I'm going to leave DS is at the childminders, and DD and I grab dinner alone, have a good chat.
The days I'm not going to be working, we generally pick up some shopping, or come home, have a snack, and watch something that she wants on TV and have dinner as a family.
Once dinner is done that's generally DDs time, so she goes to cadets or one of us goes to the gym with her whilst the other tends to the babies needs.
Our life really doesn't evolve around the baby with poor DD in the dark or parentified.
She isn't expected to look after DS except in very rare occasion for a few minutes. He is my baby, not hers. It wouldn't be fair to put those responsibilities onto her.
I think that the dynamic really changes when you have 2 children at very different ages instead of purely being able to focus on one's needs exclusively.
I'm not sure how much this would change when there are two.