It’s overpriced hardware
Have you seen the M4 benchmarks?
If you’re memory bound then sure, you can get way more bang for your buck with Intel/AMD. But for pretty amazing CPU performance I think the “Apple is overpriced” trope isn’t really true any more.
This requires us having actual conversations with those dead people to compare against, which we obviously can’t do.
There is simply not enough information to train a model on of a dead person to create a comprehensive model of how they would respond in arbitrary conversations. You may be able to train with some depth in their field of expertise, but the whole point is to talk about things which they have no experience with, or at least, things which weren’t known then.
So sure, maybe we get a model that makes you think you’re talking to them, but that’s no different than just having a dream or an acid trip where you’re chatting with Einstein.