If you assume AGI that is better than humans for effectively free of course it seems better.

But your assumptions are based on an idealized thing unrelated to anything that is shown.

No one is paying your wage for AI, full stop, you transition for cost savings not "might as well". Also given most AI cost is in training you likely still wouldn't transition since the capital investment is painful.

Robotics isn't new but hasn't destroyed blue collar yet (the US mostly lost blue collar for other reasons not due to robotics). Especially since robotics is very inflexible leading to impedance problems when you have to adapt.

Mostly though I would consider the problem with your argument it is it basically boils down to nihilism. If an inevitability that you can no control over has a chance of happening you should generally not worry about it. It isn't like in your hypothetical there are meaningful actions to take so it isn't important.