1. Agents seek to increase their profit by automating people.
2. Each agent acts to its own good but at the same moment, the ultimate goal is to get rid of all consumers of what agents produce, because jobless people are very bad at consuming goods and services.
3. Agents don't have any motivation to provide goods and services to consumers if they don't get anything valuable in return.
Conclusion is simple. Either:
a. AI development will be completely regulated and jobs will be preserved (thus negating the promised AI effectiveness), or
b. Capitalism will be destroyed and a completely new economical formation will take place.
It is AI or capitalism.
Consumers need two things to consume, money and free time. Jobless people have all the free time they could want. Find a way to get them some money to spend and they’ll consume all day long.
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.