Economics is subtractive, because resources are finite, if in some cases expandable.

And, in the context of this discussion, the lion's share of the resources needed to sustain a life are indeed expandable unless you live in some shithole in Africa or somewhere that the local environment is not suitable to sustain the number of people living there.

It's just a statistical fact. Most people are useless eaters. 90% of more of people on this continent do nothing but consume in their lifetimes.

Sure, way less people are needed to produce food and other things. I would agree that a huge portion of people are useless drains on society. The part that isn't fact is just how widely and broadly you are casting that net.

Because by having three children he'd have done the same in any other profession to boot, while contributing more positively.

I would agree that having children of one's own, especially if one is fit to be a good parent, is a fast track to being a positive contributor. But we aren't talking about contributing "more positively" or "the most positively," you made a sweeping statement about how one couldn't contribute a net positive at all unless they were a genius. Perhaps pedantic, but that is what I was taking issue with.

Teachers are especially of negative economic value(almost as much as office workers), their positive contributions largely theoretical while their profession on the whole constantly claims themselves indespensible.

I agree that public school systems and the vast majority of educational institutions are complete dogshit and net negatives overall. But that doesn't preclude there from being good individuals within those institutions that are net positives. Even looking back on my 17 years in that bullshit, there were some gems sprinkled among the shit that shined despite the shitty system they worked in.

Regarding the collapse of clown world, it depends how exactly it all goes down. If it is a true collapse of grand proportions, the death and suffering is going to be widespread among the useful and the useless alike during the initial shock. Over time there would be a re-orienting of society to be much more meritocratic, and surely the truly useful would be more likely to survive this as you say.

But "usefulness" in a hand to mouth society that is just trying to survive is a much more rigid thing than it is in a society with much excess like the current clown world.

For example, an electrical engineer that excels at his job but works at a company that produces gadgets that ultimately are not necessary might be a net negative in the holistic and transcendental sense in terms of survival. But in a situation where the societal fat is greatly trimmed down, one could imagine them potentially turning around to use their skills to support something much more close to fundamental necessities like power infrastructure or agricultural equipment. But just because they aren't doing that now, doesn't make them useless or a net negative provided whichever devices they have a hand in making are positive and not socially destructive.