Hi Erik,
Welcome to our forum...
I'm presuming the vast majority of tackle crafters dabble in the hobby and want multiple sizes for multiple applications in as few molds as possible... this was the way it was with me in the beginning, but now I've conceded and built storage to accommodate my hobby.
Given production molds do make it easier on the fella that is mass-producing, demand for such molds likely is not enough for the company to create them in every category (but only for the most popular molds). Do-it is a good company and listens to the input of its crafters, so feel free to request what you desire... if your desire for a particular mold strikes a chord with crafters and feedback is strong, that mold idea has a good chance of becoming a reality.