> All value is derived from labor... all (sensible) economists agree on this
The labor theory of value is one of multiple theories of values [1]. And it is still widely debated.
> Marx would say that the amount of value is the amount of effort that goes into the commodity, something we now know not to be true.
Marx would say the _exchange_ value of a commodity is proportional to the amount of _socially necessary labor time_ required to produce it. Again, something that debatable.
The labor theory of value is one of multiple theories of values [1]. And it is still widely debated.
> Marx would say that the amount of value is the amount of effort that goes into the commodity, something we now know not to be true.
Marx would say the _exchange_ value of a commodity is proportional to the amount of _socially necessary labor time_ required to produce it. Again, something that debatable.
[1] https://en.wikipedia.org/wiki/Value_(economics)#Theories [2] https://en.wikipedia.org/wiki/Criticisms_of_the_labour_theor...