Consoles are great. All you need is a TV, you hook it up, it takes no space and it plays games great. You take a few friends and play games in the living room.
Computers are nice too, but take more space, usually at a desk with keyboard / mouse. You need a place to use the mouse. It's big, it's cumbersome and a mess of wires. It takes way more effort to hide anything of it from view. You can't just pick it up and play and it's usually only you in the room playing.
So what if consoles have old hardware, computers do too, who's crazy enough to update them every 3 months to get the latest?