A lot of people use only that 7kg carry-on allowance to travel. 7kg can easily hold clothes, toiletries, laptop. Most of the time you can carry a personal item

A lot of people use only that 7kg carry-on allowance to travel. 7kg can easily hold clothes, toiletries, laptop. Most of the time you can carry a personal item (purse/laptop) in addition to your main bag. Thing is, the majority of people pay for a carry on allowance or checked-in luggage, so this rule isn't going to make airlines cheaper. The ticket prices will just go up to match.