Do young people still use desktop PC's?

My friend's nine-year-old uses a PC. She also plays a few games on her mother's tablet.

 

Personally, I have now switched from a powerful Windows desktop to a MacBook Pro for most of my computing needs. That includes Unity development for iOS and Android.
I still use it plugged into two 27 inch monitors, keyboard and mouse, just like I did with my desktop, so the difference in workflow only comes down to processing power (ignoring differences between the operating systems for this discussion). Luckily, I usually don't actually need more than the MacBook can provide these days.

Thanks to Thunderbolt 3, one could have a setup such as mine and connect it to the MacBook using a single cable, resulting in relatively minor hassle.
Because I don't own a Thunderbolt 3 dock (they are rather expensive right now), I have to plug in two cables and my headphones, but that is still completely acceptable.