Large screen, heavy memory units will eventually eliminate full size computers. I have only used a phablet since since 2012 sold my laptop and desktop off.
I think old fashioned personal computers will continue to exist as office workstations. For example, Boeing engineers won't be designing their next passenger jet on phablets.
And I think Playstation/Xbox/Nintendo type consoles will continue to be sold to gamers, with newer better generations of consoles continuing to be developed in the future.
But I agree that for ordinary web browsing and email, phablets are going to displace all larger devices.