Addition:

Also worth knowing: collective intellectual property already exists. ASCAP and BMI have been doing exactly this for decades. Individual songwriters can't enforce their rights every time their music gets played, so they pool their IP, license it collectively, and distribute the revenue. The problem they solved is almost identical to the training data problem. Each individual contribution is tiny, but the collective value is enormous. Applying this at the scale of the general public would be novel, but the underlying mechanism isn't. The concept works. It just hasn't been applied to training data yet.