Its still a heirloom tomato, in fact its still the tomato of old but it just has some traits have changed over the years.So in reality the Rutgers tomato is not an Heirloom tomato but instead it is a hybrid tomato that has been bred out or allowed to breed on without any new crosses being made every year, thus allowing it by genetic drift to express the undesirable traits of its parent stock as well as show some of the favorable traits that once made the Rutgers hybrid tomato popular on industrial farms.
You seem to agree with me in regards to the diminished esteem that most home guarders now hold for Rutgers Tomatoes.
This can be seen in all heirloom fruits/vegetables, over the years some traits are lost.