I believe 2010 was PS3's peak year and we will see slowly declining sales from now on. There are many reasons to this:
1. Market saturation. Most of those who are interested about this generation console have already bought them. Home consoles have been sold 180 million now and last generation had around 190 million units sold. While this generation will be much larger, even this generation have its limits. Most households still buy only 1 console per generation, multi-console households are still rare.
2. Price point. 299 € is not that much anymore, unlike last generation (inflation) so I don't think that prevents sales. Sure 199 € would increase sales but much less than dropping to 299 € did. And I don't think Sony is going to drop price by more than 50 € because I feel they are satisfied with current situation and they want to profit from sales at last. Remember, profit is more important than unit sales to all companies. Selling at loss is strategy which is meant to have big console base and profits later in console's life.
3. Blu Ray. People don't buy PS3 just for BR anymore because there are cheaper and even better dedicated players. Even at 199 € you can buy much cheaper and just as good BR players. Now, PS3's are mainly for games and BR is just extra feature.
4. Stereoscopic 3D. While 3D TV's are becoming more popular, 3D TV base is still too small to increase sales at this stage (many 3D TV's are used with dedicated BR players, not PS3). And most 3D games on PS3 are made by first and second parties. Third parties won't make many 3D games because of increased costs although it only increases sales marginally.
5. Games. Sequels on same consoles have less effect on sales than prequel had. For example, Uncharted 3 increases PS3 sales very little because most buyers are fans of first 2 games and have PS3 already. And PS3 has already had their biggest games released.










