Complex sentence: The relevant point was that price-value divergences occurred both with regard to inputs to production and with regard to outputs; but Marx himself had ignored the input price-value divergences in his simple quantitative illustrations of the distribution of profit.
Split into simpler sentences: The relevant point was that price-value divergences occurred both with regard to inputs to production and with regard to outputs. Marx had ignored input price-value divergences in his simple quantitative illustrations of the distribution of profit.