I replied to Postliterate, but I'm copying the answer here for your benefit. I'd prefer if you answered on the reply to Postliterate.

If you wish to dispute my conclusions, please provide direct quotes from Marx (e.g. from Das Kapital) to support your point. Anything less should be taken as you just spewing mental diarrhea and hoping for ignorant readers.

Marx, brilliant though he was, stumbles directly into my bouquets-of-grass issue in his very first chapter. He first postulates that things have use-value (from https://content.csbs.utah.edu/~ehrbar/cap1.pdf, section 1.1 page 4): "The usefulness of a thing makes it a use-value...the characteristic of a commodity does not depend on whether appropriating its useful properties costs more or less labor."

Okay, there are occasional, rare uses for bouquets of grass: in some unusual flower arrangements (or greenery), for movie sets, and so on. So it does have some use-value. But the value is very context-specific.

Now, Marx considers exchanging wheat (which has a use-value) for other things at various exchange rates. But, he claims: "Since x shoe polish, as well as y silk, as well as z gold, etc., is the exchange-value of one quarter of wheat, x shoe polish, y silk, z gold, etc., must be exchange-values replaceable by each other or equal in magnitude." (1.1 page 7) And, critically, for defining abstracted value: "one use-value is just as good as another, as long as it is present in the proper quantity." (1.1 page 11)

But we can throw our grass in there too. We have w bouquets of grass equal to one quarter of wheat and all the other stuff.

Here, Marx has jumped right to a stable, unchanging market. Markets aren't like that now. I don't think they were even like that then. But it is precisely this equal exchange value that Marx needs to rationalize labor as exactly that thing that remains when all actual uses are abstracted away: "If we disregard the use-value of commodities, they have only one property left, that of being products of labor." (1.1 page 12).

So, there it is: the bouquets of grass are products of labor, just like everything else, and we're done with our equal value exchange.

So, no, my criticism is directly on target. Marx's framework fails at the most basic task of an economic model, which is to understand why things cost something. It works only in very specialized circumstances of commodities where raw materials are in abundant supply and labor is limiting, everyone wants plenty of all of them, and the system is assumed to stay in balance without explaining how it stays in balance.

He concludes with a crystal-clear statement which leaves no doubt that the theory is stating exactly this wrong, grass-defeated theory of value: "That which determines the magnitude of the value of any article is only the amount of socially necessary labor, or the labor time socially necessary for its production." (1.1 page 18)

And, though I haven't had time to read the entire Das Kapital over again word-for-word, I've skimmed every relevant section of Volume I (and read the majority of the first two sections--and no, the exchange chapter doesn't fix the grass bouquet issue; it simply declares that things have use-value or not--2 page 174).

So, there we have it, direct from Marx. I'd forgotten the details, yes, but the conclusion is the same: this is useless in answering almost any economic question except in the most contrived and constrained situations (i.e. top-down mandates for exactly the right proportions of items of use-value so the uses can be actualized--e.g. 1.4 page 145, performed by workers of equal skill and training, in a society and economy in steady-state such that changing value can be neglected). In particular, it cannot explain why, given that a few people actually do want bouquets of grass, grass-bouquet-making is not an advisable way for very many people to spend their time (and why appropriately the price of grass bouquets will decrease if too many people decide it is their life's calling).