With or without the baggage limits, packing light is the only way to go unless if someone else is hauling your bags for you. I have seen carryon bag so heavy that the person had a difficult time lifting it. Of course, they expect some gentlemen to help. Usually some strong guys materialize to help. If these strong guys would stop helping, people would:

1. Learn to pack light, or
2. Check the stuff and pay the surcharge.

Besides, it is not just the airports. Train stations are full of stairs. Heavy bags and stairs just don’t mix.

Edited to include:

Helping someone really needs help is one thing. Helping someone who does not know how pack light is another.