One step further, they already have a huge training set. Stock libraries have the luxury of the hard part already being done: labeling. As of today, that's >313M labeled images they can use with no fear of legal woes: https://stock.adobe.com/search/images?filters%5Bcontent_type...

Stable Diffusion was trained on billions of images, of course. But having explored some of LAION-2B, it's clear that Adobe Stock has far better source images and labels.