Really? You're comparing Sam Jackson, who has had to do a lot of action in some movies, to the 66 year old woman who, just from a glance, is not the kind of actress who does many action movies? Thats like saying Jim Carey should play a serious FDR, or Sylvester Stallone should play Hamlet. Some roles aren't for certain actors, and i'll say right now that the 66 year old woman who is not an action star by any stretch is not the kind of person you'd hire to play an action role. Like I said, I can see a few situations where it might work, but not all actors/actresses can do everything, and sometimes it is a matter of age, and not everyone makes sense for every role. Glenn Close as an active, fighting, member of the Nova Corps is up there with the other examples I mentioned as roles actors just don't make sense for. Make her the wise old leader, it would be fine, but she's not an action star and doesn't seem to have too much experience with that stuff.
Now you're not only being ageist, you're being a typecaster. By the logic you're using, actors should only work in the niche/genre of acting with which they're most easily recognizable, and that's not the way acting works. Even a decent
actor can take on roles from multiple genres/niches of acting, and Glenn Close is a phenomenal actor, as is evidenced by the multiple awards she's either won or been nominated for.
Saying she can't do an action film just because she doesn't typically take projects in that genre is like saying that an actor or director who has only done television projects can't work in feature-length films, which is ridiculous.