Shareholder primacy certainly is relatively new, but it's also true that "the system-level goal of capitalism is to extract wealth". After that, hopefully we use that capital to produce and distribute goods "fairly".

But Capitalism isn't synonymous with the free market, or any other market configuration, and it's totally possible for the people who control the means of production and distribution to... not produce or distribute. In fact, that may be advantageous in their efforts to secure more capital.

Ultimately, "they" really always have been greedy villains. Shareholder supremacy just made it worse.