LTV was the greatest achievement of classical liberal economy, but after developing it some more, they realised that by itself it is incredibly damning to the capitalist class and its further development points on socialism (like it led Marx to) and thus the pet economists since JS Mill took a step back into the current hamster wheel in which they still run almost 200 years later. It's not coincidence that even liberal proponents and pioneers of LTV are forgotten (or never mentioned in the context of LTV) and bulk of even educated libs think it was sole invention of Marx - it allows them to claim entire scientific socialism is a cult and one single madman hypnosis over 1/3rd of humanity.