I'd say stability AI directly are not doing that very well, but the vast majority of users of image generation AI are using NovelAI or Midjourney, both of which are raking in cash and don't share their models (NovelAI seems to be at least mostly finetunes of SD, while there's not much public details on midjourney's models at all). Both cases don't have much 'big capital' (especially compared to OpenAI) though: they're just very profitable from getting on the train of making it easy to use early.
