Worse yet, PC's today are barely faster than 5 year old ones at similar price points. Moore's law ran headlong into a thermal brick wall.
That's not really true. Design rules are still shrinking at about the same rate they always did. Moore's law, after all, is about transistors and not speed. Chip makers can certainly use that extra real estate to add cores and dedicated hardware for things like video processing.
But the real problem (from Intel and Microsoft's perspective) is far more pernicious. Five year old hardware is good enough for 99% of people who need a PC. If all I'm doing is commenting on Facebook, watching Netflix movies, and doing my taxes there isn't any reason to replace my old hardware. I'm sure that's a big part of the attraction for the chip makers - they'd love to force everyone to buy new hardware in order to watch videos.