Analog film's do have higher resolution than 1080p, but it is not by default. It depends on the construction of the lenses used in a particular camera. Different cameras (like 35mm, 110,120...) use different types of analog film lens (which is basically photosensitive emulsion on a plastic sheet.). So, earlier film's were not shot with future HD era in mind. So basically if they are going to be released in bluray, it has to be digitally upscaled, and remastering of sound also will be required.
This is not completely true. The resolution of the reel film depends more on the film used. Most film reels from both Eastman Kodak and Fujifilm have been, for a long time, capable of very high resolution. In digital equivalent, the resolutions of a reel film is equal to between 2000P to 6000P. Till about 1980, the major issue with reel films were what are called
granularity. Essentially a raw film contains millions of light sensitive silver halide crystals. When exposed to light, these crystals which are free moving, become uncharged atoms. These uncharged atoms form the image that we see on the screen. Developing chemicals are used to create lower or higher density of these crystals to create lighter and darker shades of images.
Till about the 1980s, it will not possible to bind these uncharged atoms close enough. After being processed, the film ends up with small grains of metallic silver which show up as spots on the film. The issue was worsened with the advent of widescreen where you had a larger film area to cover.
In the 1980s, both Kodak and Fuji solved this problem. Kodak introduced T-Grains that were essentially larger grains that were also more sensitive to light. Fuji introduced SuperF which contained thin hexagonal tubular grains. In the case of Kodak, the new films needed less number of grains to cover the same area thus removing granularity. In the case of Fuji, the hexagonal grains were able to stick closer together literally removing any granularity.
Thus from 1980s onwards we have had very precise films, that have, as I said before, the equivalent of between 2000P to 6000P.
So what is the issue in transfer to digital formats? Basically a couple of them.
ONE, with storage, a film reel deteriorates in quality. Large gaps appear in the film, and you also get a lot of noise which we see as 'rain'. SECOND is the transfer process itself.
For a long time, the transfer process consisted of projecting the reel onto a small screen which in turn was photographed by a digital camera. Since the two technologies worked in different frames per second, there were a number of issues that were solved in unique manner including skipping every 'n'th snap of the reel film and to match the frames per second. In addition when you did this, it was difficult to clean the resultant digital image.
The new process (in which India does a lot of work) is to scan each frame and store them as still images. Each of these images are then worked upon by artists to clean them individually. Sometimes, the audio or parts of the audio are re-recorded if needed.
The cleaned images are put together to form the digital version. Movies such as 'For a Few Dollars More' were cleaned in India.
For a long time, film reel have had a density that we actually more than even our latest 1080P in resolutions. As the transfer and cleaning process improves over time, even a 1950 film can be transferred to BR or any other high digital format. The only questions remains is whether the film owner is ready to spend money to do the expensive transfer process. Movies shot in the recent past have resolutions that is greater than even 2160P. And the transfer is much simpler and economical.
Cheers
hyeah: I just got this BD yesterday from landmark for Rs.999/- (DTS-HD-MA), along with BODY OF LIES (DD-TrueHD) and Shrek The Third (DD-TrueHD), each for Rs.999/-. 
