That's where we need to ask how we define "better". Is better "when the number goes bigger" or is better "when more people benefit"? If an AI can better optimize to better extract the maximum value from people's work and discard them, then optimize how many ways they can monetize their product to maximize the profit they get from each customer, the result is a horrible company and a horrible society.

In theory yes... but what do we call "doing a better job"? Is it just blindly extracting money? Or is it something more, and do we all agree on what it is? I think there could be a compounded problem of oversight.

Like, right now an employee pays/invests some money into a retirement fund, whose managers invest into several mutual funds, whose managers invest into several companies, whose owners ask for some performance from their C-suite, who through a chain of command tell the same employee what to do. Even though it's part of the employee's capital that's controlling that company, if it takes an action negative for the employee like fracking under their home, or firing them, they're powerless to do anything about it with their investment.

With AI replacing all those steps, it would all happen much quicker, and —since AIs are still basically a black box— with even less transparency than having corruptible humans on the same steps (at least we kind of know what tends to corrupt humans). Adding strict "code as contract" rules to try to keep them in check, would on a first sight look like an improvement, but in practice any unpredicted behavior could spread blindingly fast over the whole ecosystem, with nobody having a "stop" button anymore. That's even before considering coding errors and malicious actors.

I guess a possible solution would be requiring every AI to have an external stop trigger, that a judicial system could launch to... possibly paralyze the whole economy. But that would require new legislation to be passed (with AI lawyers), and it would likely get late, and not be fully implemented by those trying to outsmart the system. Replace the judges by AIs too, politicians with AIs, talking heads on TV with AIs... and it becomes an AI world where humans have little to nothing to say. Are humans even of any use, in such a world?

None of those AIs need to be an AGI, so we could run ourselves into a corner with nobody and nothing having a global plan or oversight. Kind of like right now, but worse for the people.

Alternatively, all those AIs could be eco-friendly humans-first compassionate black boxes... but I kind of doubt those are the kind of AIs that current businesses are trying to build.