You're making a lot of assumptions about touch controls. They work much better than you think for people who has grown up with mobile only.

I honestly can't see it. Sure the kids may be fast at swiping, but ... it takes milliseconds for a professional with a mouse to already have aimed and shot against the head of an enemy player.

There is a reason why pros who play with controllers never play against pros on PC in shooters. And I can easily imagine the controller pros will be much faster than swipers.

So, for just building with blocks, I can see why parents just give the kids an ipad so they don't have all the running and screaming, but it probably won't be a competitive way of playing games. I only say probably because I just can't imagine me watching someone swiping on a screen.

I'm not saying that it will be on par with PC or even console but check out this clip where you will see the touch in action to the left: https://www.youtube.com/watch?v=nf9r5S-tnu4

The main thing with a touchscreen is that it's probably not as long term solution for input for these fast paced games. The way you grip your phone is probably going to hurt your wrists more in the long run.