What even is the economy after they have killed all the workers and it's just bots clicking on each others ads?

Then it's on to centralization of the "human" components of the workforce into company towns, robot armies and competition for natural resources that will be processed from raw.

Once the economics work out, the economy as a whole doesn't, therefore the economics DOESN'T WORK OUT.

I think you're making an assumption that the owners of this capital aren't: "That the economy has to work out for everyone."

It doesn't work out for the owners of the capital. Their wealth is entirely based on their claims on future production that is consumed by people with money.