"Highly autonomous systems" and "most economically valuable work" aren't precise enough to be useful.
"Highly" implies that there is a continuum, so where does directed end and autonomy begin?
"Most economically valuable work"... each word in that has wiggle room, not to mention that any reasonable interpretation of it is a shifting goalpost as the work done by humans over history has shifted a great deal.
The point is that none of this is defined in a way so that people can agree that something has AGI/ASI/etc. or not. If people can't agree then there's no point in talking about it.
EDIT: interestingly, the OpenAI definition of AGI specifically means that a subset of humans do not have AGI.