Imagine if each person receives a "Thing-doer 3000" then. The people can contract out their own personal robots and collect wages. The technology improves their lives, the same amount of work gets done, and the same wages are paid out.
The problem is that under capitalism, the people get replaced by "Thing-doer 3000" bots which are owned by other large companies; the people don't benefit, and ultimately it even changes the economy when people have less work due to being replaced.
People working isn't needed for a "working economy"; things need to get done, to be sure, and right now people are needed to do those things, but that may not always be the case. Making pointless work for people to do is about as reasonable as replacing taxi cabs with rickshaw drivers, and power-tools with manual tools "just because"