There is a world of difference between:

* A company following suit with their entire industry in choosing a very generous definition of fair use.

* A company being the first to defect and actually break their signed contracts with enormous enterprises committing to not train on those enterprises' most valuable assets.

Training on copyrighted works signs them up to be a part of a system that is at this point too big to fail and places them in good company with all of their competition. Breaking their signed agreements would open them up to very well-founded and well-funded lawsuits for contract violation and give their competition a huge boost.

All of a sudden "we actually don't break our contracts" would be a selling point. No company in their right mind is going to let what should be table stakes become a differentiator for their competition.