In terms of costs-it's cheaper to use the designs you already have versus do all new ones-especially if you are using the same folks over and over again.
Same with toys-it's cheaper to toss a new paint on a figure (like we saw with GI Joe's Tiger Force & Python Patrol in the 80s or the WWE toys-too forever to see a Xavier Woods figure with chest hair) than make a new mold.
So even if those films do well-unless you have a story that required a costume change-like Static-he has 5 costumes to run through if you did his origin. You won't see new designs.