I said this before and I will say it again but the whole 1080p thing has very little to do with absolute power and more to do with developer choice. Every HD game released for the past 6-7 years could have been at 1080p but rather developers opted for lower resolution with greater amounts of geometry, effects etc. Developers obviously felt that there were greater gains to be had with the latter rather than the former course. While the greater amount of power available this generations makes it easier for developers to aim for 1080p without huge compromises in other areas, it is by no means a guarantee that all games will be 1080p.
The main reason why PC games easily achieve resolutions like this (and higher) is because when developing PC games, developers have to make games that run acceptably on 'average' hardware, as that's where the majority of the market resides. Having said that there will always be a significant number of gamers that are well ahead of the hardware curve and thus have rigs far in excess of the common denominator that developers where forced to aim for.