I think that the sport that WCA comps relate to the most is Track and Field. Hear me out:
The sprint events: 2x2, pyra, skewb, squan and 3x3 for cubing, and 100, 200, 400, 800? in track.
Middle distance: 4x4, 5x5, mega for cubing. 800?, 1600 and the 3200 for track.
Long distance: 6x6 and 7x7 for cubing: and 3200-10K for track.
As for ultra long distances (marathons, ultra marathons, etc.) the only events that could compare are multi-bld, 4bld and 5bld, but I'm really thinking of the main puzzle events, and not any special categories.
Of course, there are restrictive runs (race walking, ambulatory/wheelchair races, etc.) But those are special by themselves, so what I'm trying to drive home is how similar the main puzzle events we have are close to track.
However, there are some main key differences between them:
1. In cubing, even if you have your own main events, you can still compete in other events w/out tiring out too much. In track, you're either a sprinter, long distance runner, hurdler, thrower, etc. And you aren't really going to see a sprinter doing the 3200m, or a thrower doing pole vault. They will typically stay within their main events for most meets, unless the coaches want them to try something else.
Basically what I'm trying to say here is that it's hard to do multiple events at a track meet. There are exceptions, like people who can throw down a 1600, 800, 3200 and a 4x400, or people that can do something obscure like a 1600m, 300m hurdles and a 4x400 or 300m hurdles and a 3200m run (totally not me lol). However, you usually see a distance runner do like the 1600 and the 800/1600 and the 3200, or a thrower doing discus shot and jav.
2. Cubing is a solitary sport. Sure, you can cube with friends, but you aren't going to be doing the same "workout" as another cuber, or compete in the same team in a comp. In track you warm up with the whole team in the beginner, break off to your event type, and run/sprint/lift with the people that have the same or similar event types as you. I wish that cubing had more of a team system, so that you can form a team with some other cubers, since cubing relies heavily on the teachings of others to be able to learn new things. And even if you discovered things on your own, you'd want to share them with others since we're all nice people deep down (I hope).
3. Coaching is different. In cubing you usually learn from videos online or from tips that people give you from critiqued solves. However, in track, the coaches will kind of strip down everything from form to speed to the competitions. They really push you to do your best at the meet, tell you when you need to chill at practice, you get rewarded along the way by knowing you did well at practice or a meet. They also push you try to do events you'd never normally do, or try to keep you in one event since they see potential in that ability. Within cubing, this is hard since you might be a guy that does nxns all the time and you don't really want to branch out to anything else. However, if you give them a try you might find something that you really like. That's how I got into mega, and in track, how I got into doing 300 hurdles.
So that's my rant about the similarities in track and cubing. I hope you found something interesting here, and add on.
Peace.