And on screen, it would look exactly like something a cosplayer put together in a day or two. Also, 1985.
Special effects are an art.
This. Also, film makers usually hire a special effects company to make such a suit. But there may be production delays for any reason, or the completed suit may not be good enough, forcing a redesign, or the hiring of a different studio entirely. Scheduling film shoots is a logistic nightmare. Making a werewolf suit that doesn't look like a suit, with fur that doesn't look like fake fur, and complex animatronics is a difficult task.
One of my favourite werewolf designs remains the one from the movie Bad Moon. It has one of the worst transformation effects of any werewolf movie, but the suit looks amazing.