The senate ranks based off seniority. The longer you've been a senator, the more power you yield. Senior senators get first choice of committee assignment. The longer you're on a committee, the more senior you are on that committee. So, very old person has been a powerhouse for a long time and gets to choose their committees. The more senior, the more powerful committee you can join; the longer on the power committees, the more power you yield on that committee. THE SENATE IS SET UP TO GIVE MORE POWER TO OLD PEOPLE.
She wasn't put anywhere, she chose those spots; and there isn't a damn person who can do anything about it as long as she is re-elected. Retire or death is the only way she leaves those committees. I know how this will end. As long as she gets re-elected. It's that simple.