If I'm right, and I could be barking up the wrong tree entirely, I think it's a confluence of factors that yeah, probably wouldn't happen with an American but also couldn't really happen to anyone else until very recently either.
Jess is someone who's been successful enough already that there isn't any now or never Annia 04 type energy. But not so successful that there'd be substantial commercial considerations like eg Simone would.
She's from a programme good enough for her to be able to reasonably assume she's not at risk of a Derwael situation, but not so good that she won't get back on or that she's missing out on a medal if she sits it out. It's a sweet spot.
Then there's the recent developments in the sport. Over the last decade we've seen WAGs do well after ACL tears, it doesn't have to be the end. And we now have evidence at every major championship that WAGs can do this into their 30s. I don't know if that's what Jess specifically wants, but you have to think at least some gymnasts in their teens now are looking at the Ferraris, Downies, Wevers etc and thinking yes, I could have this too. Even a few years ago that wouldn't have been the case. And so the idea of playing the long game makes more sense now, in a way that it didn't when gymnasts seldom did more than two Olympics. It's a whole career she'd be risking now.
I may of course be full of shit too.