I think the goalpost that keeps moving is for tasks that AI supposedly couldn't do, and that they are increasingly succeeding at. But being sentient/conscious is not a task. It's very hard to define and measure, even in non-human animals (actually, strike "non-humans"), so how can we so lightly claim a computer system is conscious?
We seem to be driven by marketing more than by scientific rigor.
> it’s more like we found the UFO saucer, logs of their travel from another star, a history of their civilization, a bunch of intelligent creatures claiming they came from Planet X orbiting star Y, and they showed us plausible physics for interstellar star travel
To make the analogy more precise, it'd be as if the saucer had a "Made by EarthBiz" label, and the alien creatures were all extremely loyal to EarthBiz (and a couple of competitors), which made us pay for tickets to see these ETs and use their marvelous technology ;) And of course, EarthBiz would coach their language very carefully, "we're not saying these are definitely aliens, it could be animatronics after all, but wouldn't it be neat if they were aliens? And shouldn't we draw up First Contact guidelines? If these weren't animatronics made by us; we aren't making a claim either way."