Well we can go back to the current gen. When MGS2 was shown people couldn't tell the difference between the gameplay sequences and cutscenes. And accused the trailer of being all FMV. Companies will always be able to make better CG scenes than real time cutscenes even when that gen is able to keep up with the CG cutscenes they've done in a previous gen. There will always be CG cutscenes because of that. But they could start being cut down even in the games that feature them the heaviest because they're able to get a high level of detail in real time.