Efficiency and customer satisfaction are often diametrically opposed things. Example: The Walmarts in my area all decided to implement the idea of one lineup with 10 cash registers at the end of it. Efficiency-wise, it makes sense. The rules for that line are 12 items or fewer. The line moves so fast I've never spent more than 2 minutes in it.
Customer satisfaction wise, it's a disaster. Since they now have to have most of the staff at those cash registers, only one is open for people with more than 12 items. The lineup there is, on average, 45 minutes (timed it a few times). Twice now I've dumped frozen items before buying them because they've become a soggy mess, and skipped back to the freezer to get something that hasn't been ruined from the wait.
The same can be said about a tables last policy. It benefits smaller groups significantly at the expense of upsetting larger groups who will avoid the restaurant as they (rightly) are certain there won't be seating for them by the time they arrive to eat.
From a money standpoint, one has to consider the cost of spoilage (customers with melted food, and customers with cold food asking for new hot food), the cost of turnaways (customers who won't wait 45 minutes and shop elsewhere--those abandoned carts also contribute to spoilage, and customers who don't feel secure their family will find a seat), and the average price of those turnaways (turning away customers with a full cart, turning away a 1 or 2 person party vs. turning away a Brazilian tour group).
IMHO, income is the intelligent goal here, not efficiency. I'm certain Disney carefully plans it out. Or maybe not, sometimes sense goes out the window when things get stupid (At that same
Walmart I have watched every single week customers spend 10 minutes in heated arguments with the manager, then the manager just leaves and doesn't open a register... sigh...)