This is because we originally thought "only a human would be able to play chess", "only a human would be able to drive a car". The thinking there is that if we

This is because we originally thought "only a human would be able to play chess", "only a human would be able to drive a car". The thinking there is that if we were to solve these problems, we'd have to get closer to a true artificial intelligence (the kind that today we'd call "AGI" because "AI" doesn't mean anything anymore). This line of thinking has been shown to be pretty faulty. We've come up with engines and algorithms that can play Go and Chess, but we aren't any closer to anything that resembles a general intelligence.