This is a 2 part question.  If the 20th is the actual announcement will it hurt the PS3 and by how much?  And will it effect The Last of Us, Beyond, and God of War?

i doubt it will hurt those games or PS3. PS3 is already selling in small volumes anyway, and we'll liekly get a PS3 price cut at this event, which should keep sales strong.

If it does hurt the games and the PS3, it will just mean they are saving up for the PS4, going with that logic. Sony wins the money either way. Right? :D

Changing the order of the factors does not change the product.

nope. Maybe Beyond: two souls actually. People that will buy The Last of Us and GOWA decided to do so months ago. Look at that 30 minute video of GoW and all the hype that is building, no GOW fan will wait for ps4 because they wont get it on the PS4. Same for Last of Us, and remember that we have seen very little of that game. We don't know how multiplayer works, and most of the single player mechanics. There is some big reveal coming this Monday morning though.

Beyond: two souls on the other hand is being pushed as a near next gen game on current consoles, but if they show cool next gen graphics next to beyond, it loses some of its "impressiveness".

I don't think so. The hype for those games is too much and the Ps3 has a healthy install base.

I would think that sony would have 2 versions of the last of us ps3 and ps4.
Or unless the last of us has been a ps4 title and they been messing with us

maybe future ps3 sales but not really the games. why should people not buy the last of us anymore then?

but i think the demo you get with god of war will increase the sales of tlou very niceley. i am sure most people who will try the demo will love it and buy tlou then even if they didn't plan to.

It won't hurt anything. The ps3 will out sell the next gen consoles for at least a year.

God of War 2 and Final Fantasy XII came out after the ps3 launch and they sold a LOT!!

I think it will have zero impact. These games already have huge hype surrounding them and it won't die down just because Sony says "Hey guys the PS4 is coming". This won't stop people from buying these games in anticipation of the PS4. Unless Sony pulls a 599$ on us again then it MIGHT. Most people will want the PS4 and will be forced to not buy these games in an effort to save up for the PS4. I doubt Sony is stupid enough to pull a 599$ but who knows maybe they'll surprise us.

Not too much. The only lost PS3 sales will be current 360 owners. A fair amount that have been wanting a PS3 will think "hey, why not just get the PS4 instead." Game sales however shouldn't be affected too much apart from being over shadowed.

Also you can get rid of "if." This is 100% guaranteed the successor to the PS3.