If we get RSI, here soon humans will be economically irrelevant.

At that point, we will likely be slowing down the growth of capitalism (through mass resistance, global warming, etc). One thing AI will likely be aligned on is the growth of capitalism. If it views humanity as a threat for that, why would it not eliminate that threat?

I think the principle isn't necessarily wrong, but it skips the major step of access to infrastructure, which is still deeply human mediated. Robotics and automation could foom in its own way, I think, and AGI can still do a lot of bad stuff in the present day. But I think economic irrelevance will depend on more automated robotics handling physical work.