Earlier quoted context omitted.
The assumption here is that an AI with IQ 100 could do anything a human with an IQ of 100 could do, only cheaper. But that's just averages. Really it would do half the things better and half worse, and then people have jobs doing the things that it does worse. That would continue until it doesn't do anything worse, which may or may not ever happen, but if it did and we're all still alive then the result would be post…
The power structures will never allow it. The conditions for a society of leisure have theoretically existed for some time now. We will simply end up with a a planetary ruling class that lives opulently while the other 99% live in abject poverty.
Which is why work expands to fill all available time. They want you to have a job, because what they don't want is what you might do if your time was your own. For some subset of "they" that represents the most malicious pricks.
The thing that happens if they win is that everybody still has a job even if they're not doing anything useful. Which in a lot of ways is what's happening already.