Consumer goods may indeed disappear completely from the economy, though even this does not follow from your argument.
First: Capitalism doesn't require that corporate income is distributed through wages. The "capital" in "capitalism" implies owners, who can be paid dividends from that ownership.
Second: Before transistors, "computer" meant a human. Before AI, "agent" meant human. Specifically from the perspective of a firm, paying fees to maintain an AI agent isn't that different from paying wages to a human agent, and there are already plenty of firms whose business is selling to other businesses, "B2B" is the keyword.
It does indeed require that. Otherwise, there's nobody left to profit on. Without consumers there's no business - and no capitalism.
But yes, it seems fairly obvious to me that if AI will effectively displaces all human economic value then the economy will not work for humans.
The only point I'll make on that is that I suspect you're worrying about the wrong thing. In a world where humans are economically worthless they're also politically powerless and entirely dependant on the decision making of the more intelligent artificial beings they've created. In this world your employment income will quickly become the least of your concerns.