I think PP's point was checked bags went from 2 to 1, which would mean people carry on their second bag, which they then gate check. UA may have realized people know how to game the system and are taking proactive steps not to waste the GA's time checking a bunch of carryons.

I was on a SYD-US flight and didn't notice excessive carryons, but there is one reason why you might get more - to get the duty/VAT refund you generally need to carry on the goods to show TRS inside security you're taking them out of the country. (Yes, you can go show to customs agent outside and then wait in a second line inside).