which AFAIN IANAL, copyright and exhaustive rights are completely different. Under copyright, once a book is purchased: that's it. Reselling the same, or transformed (re: highlighted) worked 'used' is 100% legal, as is consuming it at your discretion (in your mind {a billion times}, a fire, or (yes even) what amounts to a fancy calculator).
(that's all to say copyright is dated and needs an overhaul)
But that's taking a viewpoint of 'training a personal AI in your home', which isn't something that actually happens... The issue has never been the training data itself. Training an AI and 'looking at data and optimizing a (human understanding/AI understanding) function over it' are categorically the same, even if mechanically/biologically they are very different.
(that's all to say copyright is dated and needs an overhaul)
But that's taking a viewpoint of 'training a personal AI in your home', which isn't something that actually happens... The issue has never been the training data itself. Training an AI and 'looking at data and optimizing a (human understanding/AI understanding) function over it' are categorically the same, even if mechanically/biologically they are very different.