To me GPT-3 feels more like a rocket-booster than a high-altitude plane. On its own it's not going to reach the moon, but combined with the right guidance and additional thrust it just might.

I think being able to model future outcome of something in a similar way humans would (like GPT-3 does) is the first input step for an overarching AI to reach some kind of sentience.

With my admittedly limited understanding I believe that what differentiates our thinking most from other animals is that we are able to evaluate, order and steer our thoughts much better. If we can develop something that can steer these GPT-3 "thoughts" I imagine we could get quite close to sentience