Because none of them are good enough yet to trust completely with any task. Even the absolute best ones still fart out at surprising times, and for most stuff I have an AI that's always on, it requires no cognitive overhead to delegate to my own brain. So to delegate, it has to be a reliable win: I'm not here to make AI look good, I'm here to make my own performance be good, only a sure thing is a candidate for reflexive delegation.

AI companies advertise peak AI performance, users select AI tools on worst case AI fuckups: hence, only SOTA is ever in demand. TFA illustrates this well.

AI will be judged on it's worst performance, just like people are fired for their worst showing, not their best. No one cares about AI performance in ideal (read: carefully contrived) settings. We care how bad it fucks up when we take our eyes off it for 2 seconds.