In short, no. I wouldn't sell my PS3 for a PS4. I would have to be desperate to sell it – which I'm not.
The only way I'd sell it on would be if the PS4 was backward compatible with PS3 games. Obviously I'd sell it with the controller and perhaps one of two of the games I know that I'd probably wouldn't pick up again. I would have to get decent money for it though for me to consider selling it simply because it’s a great console and it’s been totally reliable to me.
I sold my PS1 this way when I got my PS2. No, I didn't get a lot of money for it (mainly because I kept all the games…) but at least I recouped some money used to purchase the PS2 and it saved it cluttering up space up in the attic. Yes, one day I'll probably regret selling it as no doubt the value of the original consoles will start to rise one day but 'meh'…there's nothing I can do about that now!