We have 3 kids and we order groceries, diapers wipes online to be sent directly.
With a double stroller, diaper bag, I suppose we could lug 2 carry on duffel bags stacked on 2 rolling bags instead of 3 big bags and 1 carry on. On spirit you still have to pay for carry on bags. Our small carry on is like a personal item (it’s compact and can go under the seat as well).
But going to a place like Mexico where we can’t order groceries and have to take allergy safe food with us, it would still be challenging with 3 kids. Something to think about I suppose