Your sticking point with my definition is that I neglected to back out the costs of the materials. Ok. I'm fine with that addendum that I should have made more clear.

But I still don't think it is an accurate theory.

I talked about times when something (umbrellas in my example) might have more or less value or a lower or higher end-price based on extrinsic circumstances - which you seem to have ignored completely.

There are times when something is worth LESS than its materials one day, and far more the next. That should tell you that the LTV has some gaping holes that fail to explain much if anything about how markets work. Are laborers being overcompensated on day 1 but ripped off on day 2? How would they know? How would anyone know? Who decides? When do they decide it?

This is messy thinking. It might work in textbooks, but markets are endlessly complex, and boiling down a theory of value to "labor provides value above the cost of materials" seems shaky at best. Value is subjective. Market participants are not static. Perhaps most importantly: ownership/management is a FORM of labor. Anyone who has worked for a crappy manager knows the importance of good leadership - it's why even market dominating companies like Kodak, GM or Sears go under and render all other labor moot.