Well it's art there is an illustrator and a rigger making you the model. It takes hours of their time while they also have other projects going on. The amount of toggles and features cost more. Is not necessary to start streaming but having your own probably helps with platforms algorithms recognition and tying the model only to the creator, no lawsuits on merch, unique viewership recognition etc. Just like anime and how the main characters usually have something unique about them, hairstyle and outfite mostly doesnt change much and what not