Actually the Xbox could do resolutions of 1200p if it felt like. The thing is that it would never have been able to handle any for of video games at that resolution. It is just like today the PS3 and 360 can handle 720p but have issues with 1080p. 1080p is a massive step up in resolution and graphical finess that is needed to take advantage. This is why its mostly downloadable small games that get the 1080p treatment and aren't just upscaled images like some of the other games.

XBOX Technical specifications
Resolutions: 480i, 480p, 576i, 576p, 720p, 1080i

A few Xbox 1 games even did 1080I. Dragons Layer and a few of the point and click adventures if I recall.

Most movies are filmed for even wider screen than current TV:s are. Biggest movies are filmed on 70mm film which has 2.35:1 aspect ratio (around 21:9 ratio). During sixties there were a lot of movies with even 2.7:1 aspect ratio. Majority of the movies are filmed on 35mm film though which has 1.78:1 (around 17:9). Yes, when these movies are shown full screen on TV, you only see part of the movie.

It can run HD, but very slowly. It didn't have an HDMI cable, so it wouldn't look good anyway on an HDTV. It also has old hardware inside it, so it could not run it as fast as PS360 can.

how does knowing if a console system can do 720p or 1080i or p, be classified as a nerd. 1080p, what it is, is coming almost common knowledge, no, if you don't know what it is, the name calling should be directed at you, not the people who know this

Actually, 35mm can accomodate both 2.35:1(Scope) and 1:85:1(Flat) depending on which lens type is in use.  I managed a theatre while in college and built movies(spliced all the reels together onto a platter system, usually around 6-7 reels per movie).  Even without the information on the header and footers of the reels, you could tell wether a film was flat or scope by looking at each frame to see if it looked stretched(Scope) or had black bars(Flat).  With flat films, not all of the 35MM frame is used.  With scope more picture information can be stored, but special lenses are needed to project it correctly.  Theatres have masking so that they can adjust the size of the screen to the appropriate aspect ratio.

If you buy the component cables and select the settings to 480P on the original Xbox and the gamecube the graphical improvement and differences are actually quite amazing. Even on the Wii the improvement is very noticeable.

I played my XBOX 1 hooked to my monitor using this adapter, I was blown away with the graphics

http://www.x2vga.com/product

Wut?

You've got it mixed ssj12. 768 and 1200 lines are computer graphic standards. Since the very start of the HDTV (I'm talking the early 80's with the ITU recommendation that set it) HDTV was defined as 1900x1080 square pixels (amongst a butload other stuff like color, luma, etc). The half-assed fake resolution standard is 720p. Heck, actually most 720p TV's actually have 768 horizontal lines and just upscale the image so the user doesn't get to see the infamous "black bars".

Additionally it's not that people think cinemas have wider screens, it's that cinemas actually have wider screens. The ratio most commonly used nowadays is 2.35:1 which is wider than 16:9. Also you can't measure the resolution of theater movies in pixels ("in the scale of the 4k+ resolutions). Film is analog and can't be measured like digital systems in pixels. In fact, there's no consensus to the aproximate resolution in pixels of film. Some experts say it's 2k, some studies say it's 4k, some papers claim the equivalent of over 4k.