In my opinion, books don’t necessarily need to give more morale, but the morale boost should absolutely last for much longer than it does. As has been stated already, I’m unlikely to even remember what I ate yesterday, no matter how good it was, but reading a book stays with me for days or even weeks. (As for alcohol, I’m more likely to feel like garbage the next morning rather than have any lasting morale boost - adding a hangover debuff that kicks in 6-8 hours after drinking might help a lot with that.) It doesn’t even have to be a “good” book - if you’re in a hellish situation, any kind of escape into a story world is going to provide a huge benefit, as long as you don’t hate reading.
As for re-reading, I find that (in real life) I often get a much higher boost from re-reading a book I’ve already read than from reading a new book. When I finish a book, and I have a choice between starting a new one or re-reading an old one, it’s about a 50-50 split which one I’ll choose. A new one might be amazing, but the old one is familiar and requires less effort to read since I’m already familiar with the story. Of course, I don’t re-read every book, but you might be surprised at the ones I choose to re-read - not necessarily favorite books, but just anything I didn’t actively hate the first time around. And sometimes even ones I did actively hate the first time around, to find proof of why it’s awful or try to remember what was wrong with it. This is not a rare thing. People will often gravitate to the familiar, and the idea that after a book has been read once, no one would ever want to read it again, strikes me as a little absurd. I might read the same book several times per year. If I only had three books I would greedily read them over and over again until I could recite them from memory, even if they were books I didn’t like. I wouldn’t read them once and then declare them useless and chop them up for scrap paper. In fact, if anything the morale value of a book would decrease for me slowly over repeated readings, rather than needing time to “recharge”. If I read it five times, it would give a very low boost for at least a month or two, just because it’s mostly memorized at that point.
Here’s an article exploring some reasons people repeatedly consume the same media.
I wouldn’t necessarily say that books need to give a higher morale boost, but I’d absolutely request that the boost last for longer. At the very least, even if books in general aren’t changed, I’d like to see the bookworm trait buffed so that book morale boosts last longer and books can be re-read, at the very least for reduced morale, at least once or twice. Right now there’s basically no value in taking the bookworm trait. And as a real-life bookworm, I can assure you that it is absolutely realistic for books to boost morale for long periods of time, and for repeated readings to have value (sometimes even more value than the initial reading), even without a break between readings. And as a real-life bookworm who has used books (even random books) to escape from and survive trauma, I hope that my experiences are seen as valid for the context of CDDA.
(Tangentially related, we should not be able to play an instrument while reading or crafting. That is an infinitely renewable morale source which doesn’t even use up time. Of course, I would guess that’s probably not an easy thing to fix, but I do hope it’s on the list if at all possible.)