jabird
They are doing so because it has become so expensive to shove these bags in the hold.
Uummmm, I don't think so!!! As I understand it, the first surge in cabin baggage was when Hub-and-Spoke operations really got going. Since so many pax found that their bags did not make the connection - they started taking them in the cabin.
This beahviour then spread because the carriers did not stop people doing it for very sound commercial reasons. This very quickly became the 'SOP' of all pax to be able to take more weight than allowed.
Then the LCCs came along with new rules and capitalised on existing behaviour. Some wanting pax to check in the bags and others wanting them to not check in bags.
I know, I'm old and been paxing for too long. All those wasted weeks of my life watching pax in airports and aircraft ...