Roles go away and fewer people are needed to do a thing, but I think it's good! For example the number of people on farms decreased orders of magnitude over the past say, century - yet we still feed everyone. Farming got mostly automated and got insanely more productive per human.
What happened was those people who would've been needed on farms went and did other stuff and the economy got way more complex but also that new complexity let a lot of more awesome things got provided for a lot more people by a lot more companies, a trend that continues today.
If you want to be a farmer good luck; it's harder to get started than it was say, 50 years ago - so why bother when there is no net new demand for farmers and there are also many better ways to make a living.
That's what'll happen for cognitively drudgerous work vs. creative new work.