If there is a plenty of revenue, profits, and taxes paid by businesses - and if there won't be, there's nothing to talk about - it will mean there will be no AI productivity boost - why won't society find something for those people to do? Even if solution is as simple as "conscript men to the army and send them on conquest, and pay women to have children"? Older ones usually have enough investments so in conditions of economic boom => rapid stock appreciation, they will be OK.