While that might be true, look at actresses like Jennifer Lawrence who is part of two big franchises; The Hunger Games and The X-Men Trilogy, yet has managed to juggle both, while also starring in smaller movies in-between those franchises shooting schedules.
Unless the SW shooting schedule is incredbilbly grueling, i'm sure she'll have a month or two for shorter shooting schedules of other movies, in-between her SW obligations. Once December roles around, she's going io become an international star. She may even become the new 'it girl' ala Jlaw. She's going to be getting offers out the wazzo, and i'm sure her agent and management are planning on taking advantage of that, as they should by booking her for other parts......