Style transfer combined with the overall coherency of pre-trained models is the real power of these. "Country house in the style of Picasso" is generally not how you use this at full power, because "Picasso" is a poor descriptor for particular memory coordinates. You type "Country house" (a generic descriptor it knows very well) and provide your own embedding or any kind of finetuned addon to precisely lean the result towards the desired style, whether constructed by you or anyone else.
So, if anyone believes that this thing would drive the artists out of their jobs, then removing their works from the training set will change very little as it will still be able to generate anything given a few examples, on a consumer GPU. And that's only the current generation of such models and tools. (which admittedly doesn't pass the quality/controllability threshold required for serious work, just yet)