Learning new things takes time. When we were inventing new machines once per generation, that means workers needed to learn new skills once per generation, which is completely achievable.
If we can train AIs faster than human beings can learn new things, there's no way for people to keep up. Even if AIs are a bit slower that's still an issue. Imagine getting a new masters degree every 5 years.
Why is that an automatically agreeable opinion? There are a lot of people in professional trades who go to school once in their career, and then periodically augment their skills. But they don't go and get a whole new degree every few years just to continue to have a job
If we can train AIs faster than human beings can learn new things, there's no way for people to keep up. Even if AIs are a bit slower that's still an issue. Imagine getting a new masters degree every 5 years.