I think Sadie was a victim of the era. At the time, everyone would have assumed the male was the brains behind the outfit, and that the female was around primarily to keep the caffeine flowing and to type up letters. Sam could have done a lot more to dispel the notion, but I do wonder if in some regards he bought into it as well. I'm not sure he ever truly believed Sadie was an equal partner, particularly after Max died. And it certainly didn't hurt that he handled interviews so much better than she did.
Today, I think it would have been more challenging to have buried Sadie's contribution to the team. Given the fact that Sam was so much more personable, though, she likely would have taken a back seat regardless.