No, people didn't say this ever. People always had the necessity of playing music in a portable way. Before MP3 players there were discman, and before, walkman, and before, batteries-enabled radiocassetes.
No, I'm saying people always said that everyone would always need real home stereo systems, but now we've reached a time where 99% of people listen to music on laptop speakers, tablet apps, or docked iPods.
(I can see I didn't make this point very clearly, since everyone read it as saying the opposite of what I meant.)
Tablets will never get home console place because you will always be able to have more graphical power in a console than in a tablet.
Well, this assumes three things: linear growth of graphical capacity, linear growth in developers' capacity to
use graphical capacity effectively, and immobile hardware strength relative to its portable equivalents.
On the plus side for stationary hardware, battery tech has been stalled out and that's a pretty big damper on future mobile-hardware plans. On the minus side, though, there's a lot of reason to believe that we're hitting a soft ceiling on developers' ability to maximize new graphical hardware as well as consumers' interest/ability to distinguish it, and the gap between what a console-sized device and a tablet can do has been getting smaller.
You always have been able to connect a DS3 to a PSP
Nope, only the Go (i.e. the model no one bought.)
on the other hand, using your $600 tablet as poor replacement for $69 Roku, does not make any sense
Well, that's just the thing. The Roku is a commodity device. Pretty soon you'll be able to get something that provides all its services for $30 (or they'll all start coming built-in to every new television.) That service is
so cheap that it isn't actually an advantage to converge on it. The expensive part of a game console is the hardware that lets it actually play games and that's what can be challenged by other hardware.
Also, tablets aren't going to stay in the $500+ price range for long. Amazon and B&N have already put out mass-market $200-$250 tablets and the capability of such devices is just going to go up over time.
That really doesn't address why you think people will want to own a tablet and nothing else for their home entertainment.
People will want to own whatever has the entertainment they want on it with a value proposition that makes sense to them. A tablet device with Bluetooth and HDMI is capable of providing all the benefits of a home console while also providing flexibility and features the consoles can't. My question is: what factors make dedicated handhelds vulnerable to the (very real) threat of convergence but isolate consoles?