You are looking at this from a technical point of view. I agree, pc is better, and for the record, I like pc and consoles.
But remember that a lot of ordinary people are buying branded desktops and laptops. They have no interest in building their own. This often means they are trying to play games on integrated chipsets, or very weak discrete chipsets. That is why the steam survey reflects this. The pc gaming industry is bigger than the technical people running the latest and greatest. The machine simply wasn't meant for gaming, as they were probably looking for a good deal, and from a gaming perspective this leads to disappointment.
Consoles are built with gaming as the primary use. It's plug and play most of the time. Sure, the console graphics look dated toward the end of its life span, but that is the trade off.