system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why did we go through this huge change from 4:3 TVs to 16:9 TVs, only to have all the movies now come out in letter-boxed 2.40:1?
gpt
2.40:1 isn't really new -- it and 1.85:1 have been cinema film standards in the US for awhile now. Even though the movies you used to see were in pan and scan 4:3 formats, the original footage was in widescreen.

As for going 16:9, it's been stated that that specific ratio is a compromise between many other ratios. As HDTV broadcast expanded, that format was adopted for it, so it stays.

There are TVs in other formats, but they're not common, and they're not "the standard".