> The other commenters arguments...seem more convincing
Because you (and I) want it to be fair use. But as I already said in my comment, it potentially fails one leg of fair use. Keeping your purchased physical copy of the book pristine and untouched while you read the photocopy allows you to later, after destroying the copies you made, resell the book as new or like-new. This directly affects the market for that book.
Do you want to spend time and money in court to find out if it's really fair use? That's what "no precedent" means.
No. I'd much rather pirate the epub followed by lobbying for severe IP law reform. (Of course by "lobby" I actually mean complain about IP law online.)
If there's no epub available then I guess it's time to get building. (https://linearbookscanner.org/)
And whether or not I am personally interested in testing any of these opinions is completely beside the point.
The idea that photocopying a book for archival purposes is potentially fair use is an untested opinion. I'm not denigrating that opinion. I just think it's likely to fail as an legal argument in the unlikely event that it comes up. I'm not a copyright apologist.
I myself believed the "fair use for archival"/"format shifting" thing applied to all works for most of my life. I only learned there was no law or precedent like 10 days ago.
Why do you interpret this to mean "absolutely can't do this"? "No precedent" seems to equally support both sides of the argument (that is, it provides no evidence; courts have not ruled). The other commenters arguments on the actual text of the statute seem more convincing to me than what you have so far provided.