If they released PS5 in 2015, yes. But the PS4 isn't going to be replaced anytime soon. RAM usage will increase over time, so saying something like "pc games uses 3gb right now" doesn't mean anything, cause the PS4 isn't designed for the present only.

Epic had a hard time convincing MS that the 360 needed 512MB, and this pretty much saved the console.

At launch it is overkill. Even after the second wave of games it will be overkill. In 7 years though it could be the bottleneck. Sony doesn't want a repeat of this gen. I expect EVERY social feature in the 720 to be ported to PS4 now that it has so much extra ram.

It's not that bad, since Microsoft will probably double that amount with the Xbox 720.

I agree, 3gb of ram just for the OS means it's a chunkier OS than even Windows Vista and certainly a massive jump over the Xbox 360's 32Mb-48Mb~ OS that it has right now.

Also, the PS4 doesn't have a "Ram advantage". DDR3 is lower latency than GDDR5, whether the DDR3's bandwidth will hold back the Xbox 720's fillrate at 1080P remains to be seen, but even after a couple of years I expect both the Xbox 720 and Playstation 4 to start having it's games run at 720P again, so that bandwidth advantage should mean less.

We also have no idea if the PS4 has a 64bit memory bus or a 128bit memory bus or if the Xbox 360's memory bus is 256bit, DDR3 with the right set-up can be competitive with GDDR5 in terms of memory bandwidth, it's probably something we won't know 100% untill all the cards have fallen into place.

The GPU doesn't even have enough power to utilize 8 GB.

Double that amount in GDDR5 or GDDR3? There's a difference.

For 170GB/s? 256bits.

8GB is not to GPU alone... it is to all the system (CPU, CPU, etc)... anyway there is no relation in GPU power and memory size.

This is shared memory... I thought you knew that?

I hope not, that has overkill written all over it.