Sorry to double post, but I figured out that it's their bookcases at the Landgraab house. I bought a new bookcase and was able to purchase books. None of the existing bookcases allowed for that option, however.
@simfulicious, this happened to me today as well. I don't move into pre-existing households usually, so the missing Purchase Books option surprised.
Like you, I replaced the bookcase with a new one.
Similarly, I had a problem with the fridge, the workout equipment, and the computers.
Fridge: Lol, I already forgot what my problem with the fridge was, but replacing it fixed the problem.
Workout equipment: Also, the Bodybuilder aspiration's "Own 2 pieces of workout equipment" wouldn't count the Landgraabs' treadmill and workout machine. When I bought new ones, however, that requirement triggered.
Computer: I couldn't "Order Parts" from the pre-existing computers and had to replace one of them for ordering upgrade parts.
