While the Marxist theory of value is flawed in all contexts, one could at least understand the nature of the error in the context of pre-industrial society ... because the contribution of intellectual capital to human productivity was much lower than that in a capitalist, industrial society. To hold the labor theory of value today that “each man-hour of work is identical to any other” is to evade/ignore facts of reality.
Consider the obvious difference in output when the same person uses a manual hammer to drive nails vs using a pneumatic machine. Someone had to invent that pneumatic machine, but would anyone insist that the same hourly rate is justified in both cases?
Even in a post-industrial, capitalist country, compare an equal amount of time spent on two different jobs: one person’s day spent on using a pneumatic machine and another’s in developing the pneumatic machine to be produced at a factory, backed by the investment capital needed to produce such machines. In each case, note that the more capital (economic and intellectual) that is behind a job, the more the value generated.
The Marxist attack on “value” is an attack on man’s Reason, which is the source of all forms of capital. The same evasion that supports this flawed theory also feeds the furor over “inequality”.