Unless you can provide some very surprising evidence backing this claim, I'm going to have to call bullshit. Sales of console and handheld games and hardware have been steadily, reliably increasing since the 1990s, and the industry's rate of growth has started to increase exponentially over the past few years (source here).
Not only that, but Steam Link was only released earlier this month. Even assuming it will take a chunk out of console sales, there hasn't been enough time to see evidence of that eventuality. If Steam Link was just used as an example of devices that allow PC games to be played through the television, you run into the same problem. That tech has only been available/known to mainstream consumers for about a year and a half. Still not enough time to prove this point, even if it wasn't based on false assumptions.
Lead me not into temptation... I can find it myself.