As a former top-level high school/college track and field competitor, I can tell you that track and field has a much more "urban" flavor[0] than, say, sailing. I always took sports such as lacrosse to be "sports white people play", but I guess wealth could be an indicator, too. Dunno, I was never rich enough to find out.

[0] Yes, that high-pitched sound you hear is a dog whistle.

Sports can be weird and very fluid indicators. In Australia where I grew up Rugby League was played in public schools and Rugby Union in private ones, so union was associated with wealth. 20 years later union is often played in public schools in the poorest areas by migrants from the pacific islands and the indication is reversing. Every second house a swimming pool there (and beaches), so swimming wasn't seen as a wealthy activity like it is in other parts of the world/country. If you compare between countries it gets even weirder, we inherited almost all sports from England but for them tennis and cricket are they snooty sports, here they're firmly working class.

Soccer and basketball for whatever reason seem to hit that egalitarian sweet spot.

For most of track and field all you need is a half decent pair of shoes.

Contrast that to hockey, lacrosse, or polo.

It's not "poor" as much as it's "not rich". Also, something to do with skin color.

(think of the demographics of many of the people who excel at many of those events...)