They still are, as a whole. They'll regularly tell you sit down rather than wait in the aisle. Some are more forceful than others. One other thing I find different in the US is that the crew are less keen to engage in a chat than BA crew. Often people will queue for the front toilet and chat with the BA crew, but on US domestic flights they are more keen to just get on.

It can be a bit frustrating for crew when you get 3 or 4 people queuing in the aisle for the toilet, whilst they are trying to perform their service.