That’s not how the Room of Requirement works. As Dobby describes it to Harry, you need to have “real need” of it to be able to access it:
“Because it is a room that a person can only enter,” said Dobby seriously, “when they have real need of it. Sometimes it is there, and sometimes it is not, but when it appears, it is always equipped for the seeker’s needs.”
— Order of the Phoenix, chapter 18 (Dumbledore’s Army)
Since Harry et al. can get all their school books from Flourish & Blotts or the school library, it would be hard to argue that they genuinely “need” these books from the Room. I don’t think it would be forthcoming to such a trivial request.
By contrast, the DADA books were probably inaccessible to Harry et al. We know that Umbridge read all student post (so a mail order from F&B was out-of-the-question), they couldn’t get to London to buy them in person, and there’s no way Umbridge would approve them for class or allow them in the library. (Okay, we don’t see her banning library books, but would it surprise you?)
Edit: I would add that the Room was almost certainly installed by one of the Founders, who was a teacher and thus understood children. I’d be a little surprised if they didn’t spot and close this loophole.