The problem is that eventually it becomes ridiculous to the extent that the process feels, well, just mean. For example, budget flights in Europe have no cabin

The problem is that eventually it becomes ridiculous to the extent that the process feels, well, just mean. For example, budget flights in Europe have no cabin baggage included other than a very small bag. There's enough space in the cabin, and logically the cost of adding another 10kg to each person can't be more than 10-15% of the ticket, but it's way more than that to add a normal sized bag.