Marx himself said something like this in Capital I, Chapter 25,
pp. 773/4 in Random House edition:
This law of the progressive growth
of the constant part of capital in comparison
with the variable part
is confirmed at every step (as already said in the earlier development)
by the comparative analysis of the prices
of commodities, whether we compare different economic epochs
or different nations in the
\randpage{774}
same epoch.
The relative magnitude of the part of the price
which represents the value of the means of production, or the constant
part of the capital,
is in direct proportion to the progress of accumulation,
whereas the relative magnitude of the other part of
the price, which represents the variable part of the capital, or the
payment made for labor, is in inverse proportion to the progress
of accumulation.
