That’s the whole point of boarding earlier, securing carry on space.

I’m little skeptical. Even before most airlines started charging for checked bags, they had first class board first, and then boarding groups by status. When checked bags were free, the overheads didn’t fill up very fast.

Frankly if I’m at the lounge, I’d much rather stay there another 15 minutes than spend it in a metal tube at the gate.

I think people want to board earlier because the airline says that earlier boarding denotes high status, and people love to be on top of a status game. It’s great to have the velvet rope open in front of you and be told you can go first. Unfortunately at the airport going first just means you get to sit in the tube longer.

If you watch on domestic flights, it's about a 60-40 split between people who put their carry on near them (60%) and people who throw it in the first free bin (40%)

But how much of that is because boarding is a complete mess, and the last thing you want is to get to the back of the plane where your seat is and that's all full already because for some reason all the people with status are also in the back. Then you have to wade "upstream" to put your bag somewhere.

If the plane was more reliably boarded in some sort of order, I'd be more relaxed about it.

In my experience, it’s super common.