Today's "normal pc" compute power is inadequate for 4k video ... Unless you plug in a decent gpu and your machine includes a decent bandwidth to that gpu.
Given that parents have always wanted to film thir kids at the highest quality they can afford, where do you thnk this trend might take us industry wise?
Edit: if i cannot type out this post error free, mobiles phons suck as PC replacements ;)
Yeah, but just like the PC, phones are never going to replace reflex cameras, for a number of reasons I will not develop here. It's not because a market actor gains or loses that it wipes the entire market - and that was Dustin's entire point.
I think the future is coming to your office and getting a bigger screen via a wireless connection to your tablet automatically (like Surface Pro with Miracast). You even said "27 iMac" instead of "powerful iMac".
The migration factor would seem to be an important part of Dustin's point—along with the idea that teens and 20-somethings are leading indicators, as they were for social networks, mp3s, etc.
(I'm typing this on a 27" iMac but would broadly define myself as part of the "specialist" group.)
Incidentally, cameras appear to be following a similar trajectory to PCs, with sales falling off in the last two or so years. See e.g. http://www.dslrbodies.com/newsviews/when-will-the-panic-star... or http://www.dslrbodies.com/newsviews/march-2014-nikon-news/ha....