Didn't the industrial revolution increase working hours? Automation mainly just makes more, shittier, work, as human agency gets removed. Other than occasional instances of someone automating their job and not telling anyone, are there examples of automation actually letting people work less?

Pedantry: depends on your definition of work. If you mean "expend calories", then yes. If you mean "have more free time to call your own and not your employer's", then no.

ChatGPT can't do anything, but legislation can, once the social consensus build enough. Just as it did for the 40 hour week.