I used to work security at an ER at in a medium sized city (400K pop). There were many times the ER was overloaded and people waiting in the halls, in the lobby, etc overnight. Long before COVID. So many factors such as one major wreck can pull the on-duty ER staff and backup the normal flow of broken arms, high-fever, heart attacks. Short staffing of doctors also caused some backlogs. If the media wanted to find a couple of overstuffed ERs in the Dallas area, that would be possible on any given day regardless of Covid. That is my personal experience - not hearsay.