Labour law alone, in terms of the terms under which people are employed and how they are paid, does not protect freelancers from the scenario that you, and so many others, advocate for: a multitude of individuals all training their own AIs. No AI advocate has ever proposed a viable and practical solution to the large number of artists who aren't directly employed by a company but are still exposed to all the downsides of unregulated AI.
The reality is that artists need to be paid for their work. That needs to happen at some point in the process. If AI companies (or individuals setting up their own customised AIs) don't want to pay in advance to obtain the training data, then they're going to have to pay from the profits generated by the AI. Continuing the status quo, where AIs can use artists' labour without paying them at all is not an acceptable or viable long-term plan.