MG Siegler is very much wrong, and its got nothing to do with how powerful PCs are - the problem is that PCs have mice and keyboards where phones and tablets dont (unless you want to be this guy)
http://thedoghousediaries.com/4557
I challenge you to write your next blog post (including research, image editing, uploading - the lot) on something that isn’t a PC.
Sure tablets are great for browsing the net or checking e-mails from your sofa, but once you try to do anything more complex you find that touch screen interfaces alone simply aren’t as good as a keyboard and mouse for the vast majority of tasks (maybe they will be in the future, but they aren’t there yet)