As if to illustrate my point, USA put two steeplechasers and a hammer thrower who haven't competed since the US trials and haven't competed outside the US all season through auto-qualification. None of them are nobodies, but somebody outside the US will have only seen them at all if they watched the Eugene DL. Constien barely runs - has about 4 or 5 times a year - and has only run outside the USA once since Tokyo. Wayment runs more frequently, but only did one DL last season, in Zürich, and one Continental Tour ahead of the Worlds in Budapest; and in 2022 she only did one race outside the US. Finally we have Marisa Howard, who apart from two entries at the Pan-American Games last ran outside the USA in 2017.
Howard is a bit of a wildcardand indeed did not make it through, but the other two are well established runners - but for anybody not in the USA where these domestic events get any coverage, you could be forgiven for thinking they came out of nowhere.
And then Jasmine Jones wins her 400mh heat at a canter, having only ever run outside the USA once before, at the Pan-American U20 championships in 2019. She's clearly fast, and she's young, with super results on the domestic circuit. But anybody who follows athletics but is not from the USA will never have had the chance to see her run, so for those she will look like a complete out-of-nowhere magic appearance.