> No, that's not the most important factor. The transformative factor is the most important.
It's a four factor test because all of the factors are relevant, but if the use has negligible effect on the market for the work then it's pretty hard to get anywhere with the others. For example, for cases like classroom use, even making verbatim copies of the entire work is often still fair use. Buying a separate copy for each student to use for only a few minutes would make that use uneconomical.
> Effect on market for the work doesn't even support your argument anyway. You're argument is about the cost of making the end product, which is totally distinct from the market effects on the copyright holder when the infringer makes and releases the infringing product.
We're talking about the temporary copies they make during training. Those aren't being distributed to anyone else.
> So? That doesn't make you right.
Making a copy of everything on the internet is a prerequisite to making a search engine. It's something you have to do as a step to making the index, which is the transformative step. Are you suggesting that doing the first step is illegal or what do you propose justifies it?
> By that logic, anything that's expensive becomes a fair use. It's facially ridiculous.
Anything with unreasonably high transaction costs. Why is that ridiculous? It doesn't exempt any of the normal stuff like an individual person buying an individual book.
> They don't need to get every single book ever written.
They need to get as many books as possible, with the platonic ideal being every book. Whether or not the ideal is feasible in practice, the question is whether it's socially beneficial to impose a situation with excessively high transaction costs in order to require something with only trivial benefit to authors (potentially selling one extra copy).