In the beginning it will be used for the "being lazy" again.
I mean with current consoles devs were forced to optimize the hell out of their code etc to make the games run etc... with Sony's 8gb of ram they can finally throw unoptimized "mess code" at the console.
I am pretty sure we will have games alot of inefficient games in the beginning and in a few years we will finally have games that make use of the 8gb of ram (well 7gb for games)
The games we will see in the first 2 years might work with 1-2gb of ram but because they are unoptimized they will use need alot more.
Devs might do this because a) its a new generation and programming is a bit harder than with consoles you had 7 years with. 2) it saves alot of money and because 1GB of ram is still 4x or even 8x the ram of ps360(depending on how you look at the PS3's ram) and its faster anyways we will still see a difference in graphics so there is no need right now to "use" all the Ram.
P.S. the "lazy" thing is also the reason why you read that devs love the huge amount of ram.
