This is accurate, but it goes beyond backstage politics and issues, I think. The problem with an actress being too beautiful is that they alienate a huge portion of the audience. Most women aren't going to empathize with some hugely attractive female character on screen; they simply aren't going to relate. Also, after a while, most men are going to get tired of the looks; this is the same principle which drives the huge turnover in porn actresses.
There are three categories of actresses: one, the fine category, as you mentioned. Like porn actresses, they tend to burn out really quickly i.e. no one's seeing any Angelina Jolie movies nowadays. Two, the plain/overweight actresses. If they're lucky, they can carve out a career in character work e.g. CCH Pounder, Margo Martindale, Kathy Bates. Three is the sweet spot, the attractive/cute enough to be above-average looks wise and relatable, yet not attractive enough to be threatening i.e. Meryl Streep, Sandra Bullock, Viola Davis. .
. She might not be blockbuster movie material but with all these lame ass TV shows around, surely those credits should be a lot stronger than they are (only two main roles according to Wikipedia).
