Cross-buy is something thats for PSN titles only like small games or indie games. Never has there been anything such as "buy this old copy and once the new one comes out, its free". (For retail games even Digital ones) The closest we got was when the cross-gen games came out that had a $10 "upgrade" and by upgrade, you must keep your old disk in the system to play the new one. (why? because companies are not gonna just give you a free upgrade of a full retail title.)
And for that forum reply. Guess this is on that dude person but my feeling was that it was a generic response to try to answer these questions. If there was an "upgrade" path, this shit would of been settled weeks before release.
Here is what we knew last year, a rumor about TLoU PS4 port coming for it. Once you know this, people should of avoided buying the game. Im being honest. I couldnt stop myself getting the game but I opted out of getting the Season Pass and missed out on it. Well I knew this was coming. Saved myself $20 which is going to the new copy. Sometimes people shouldnt be buying a product if they know an improved version is coming out later.
Now if you bought TLoU PS3 Digital...well digital content on PS3/360 is still really iffy. Its a closed market so prices will remain high and sales are not as many as say Steam. Knowing this, you took the risk of spending top dollar on a digital copy that you knew had risk and downsides to it. Physical copies drop after time unlike digital and there is no expectation that that digital version of the PS3 copy is gonna grant you a free or discounted PS4 copy. Use common sense, cross buy is not for retail games. I feel that ND guy who replied to the discount question shouldnt of done it as now people are hopeful for something thats 99% sure aint happening. Sorry for a nasty reply though