She makes the part believable, so does the actor who plays her lawyer, Kelly McGillis who does not act these days which is a shame.
Strange comment to make.
Kelly McGillis was in Stakeland in 2010, has made a further four movies since including one in 2012, and has also appeared in TV programmes and on stage.
She was never a very prolific actress - at the height of her career she was only making two or possibly three movies per year. As she has made four in the last three years, this is not really any less than in her heyday.
Or do you mean that she is no longer a highly paid A list actress like she was in Witness and Top Gun (and The Accused)? Well, the same can be said for many actresses in their mid fifties. Doesn't mean that they no longer act.