I don't think they killed it, but average Joes will be buying laptops instead of desktops for the foreseeable future. They have all the power needed for the basics.

I definitely see desktops becoming how laptops were years ago: a niche market. If you need a specific feature: i.e. lots of power or high-end gaming, you go with a desktop. Years ago people only got laptops if they had a specific need for mobility. The default option has already changed from desktop to laptop.