Several of those movies were ones that I did search for closer to when they were out, so they must have acquired the rights in the meantime. But that's another

Several of those movies were ones that I did search for closer to when they were out, so they must have acquired the rights in the meantime. But that's another of their problems: why would I look again when it wasn't there before? Contrast this with the DVD/Blu Ray model: if it's available for sale you can rent it from them. There's not a mishmash of rights and availability dates.