system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is it team Great Britain in the Olympics but England, Scotland, Wales and N. Ireland in other tournaments, such as the World Cup?
gpt
Football (and Rugby, and Cricket) got their start on the British Isles.  The first international football match was an England vs. Scotland match in 1870, and there was a yearly "Home Country Championship" in Football nearly 50 years before there was a World Cup.  

So by the time Football spread to the rest of Europe and the World, there was a long tradition of the British Countries competing separately, and it was natural for them to apply separately to FIFA for membership.  

Compare with the Olympics, which at their start in 1896 consisted almost entirely of individual events.  There was no comparable long history of England vs. Scotland forming teams and competing against each other in Track, Bicycling, or Wrestling, so no reason for them to form separate teams in those events for the Olympics.  When football was then added to the Olympics, it was just one event among many, so there'd be no reason for Great Britain to separate just because of that.