If they're playing it safe, it's because they think it won't sell. This is what businesses do, they're trying to make money, remember? Whatever data they have, whether that's from previous attempts to bring back these themes or whatever, they don't seem to be to their satisfaction.
They may try again in future, we don't know their business plans. I also don't think we have enough evidence to say with confidence that they're not doing it without good reason.