I’ve definitely heard of the exchange still happening…
Yep, it's still happening. This year's exchange took place in June in Cologne. Canadian franchises are still taking part in it (well.. now it's only the French-Canadian one).
The US has stayed truer how?
If you take the US' campy editing, it certainly moved away big time from its original roots. If you define Big Brother as "viewers decide" (which is fair for UK/Australian audiences, where they use that tagline), then BBUS is obviously also quite far away from the concept. But if you use a broader definition, then BBUS at its core is still somewhat close to the original idea of Big Brother.
What is Big Brother? How would you describe it? It's a show where a bunch of strangers live together under one roof, being cut off from the outside world and watched 24/7 not just by the producers but also the public. Periodically, some of them get nominated for eviction and one of them gets evicted until one winner remains.
All of this is still true. The only thing that is different is that the housemates evict one of their own versus the public deciding. That's the only thing that's different. Other versions changed way more.
@Kingston mentioned an important and probably the most important factor: live feeds. Almost all main franchises got rid of the live feeds at some point (or at least tried to), taking away the viewers' chance to watch 24/7... turning the show from 24/7 multi-platform experience into a TV show like many others.
Not all housemates around the world are cut off from the outside world anymore. Germany went back to having competitions in front of a live audience, giving the housemates a chance to read all the posters and to interact with the audience in some way. A lot of international franchises have the hosts discussing the week's events with the housemates and thus getting input from the outside world. The Indian versions somewhat lives from the host getting angry with some of the housemates. Just search for "Salman Khan confronts" and you'll see a shit ton of videos. Italy has "opionists" that chime in and can even hand out immunity.
I think the US version of the show still incorporates some of the ideas that Endemol had in the Netherlands in 1999. For their first season (and that's quite unique for that season, Germany didn't follow that approach when they launched), they've cast the housemates like members of a family. Casting for drama and conflicting views was not on their mind. The drama came from the nominations, which added an element of betrayal for them. It's the moment where you go against your family. And betrayal is a core element of the US version these days. And you can take that point in general: What the US has done with their concept is more about highlighting dynamics that have been in place in the first season than re-inventing the wheel completely. It still had drama based on conflicting views, it forced housemates to work together in the shopping tasks that got turned into food comps. It still had nominations. (Also, while we're talking about nominations: The first alliance on Big Brother happened before the US version even launched!)
Quite a few versions around the world got rid of any nominations process and thus a chance for betrayal. The most famous example might probably be the Swedish revival, which for 2/3 of the season had competitions to determine the nominees because production reasoned that nominations aren't good for housemate's mental health. Two years ago, The Netherlands followed a similar model to the US where usually only a competition winner (or winners, in rare cases) nominated. There are still versions that are so random with their nominations, that I very much doubt that housemates care about being nominated by somebody else in the house.
I also think that the US version at its core is still more of social experiment than many other versions, if you want to use that definition. Grodner gets a lot of shit for her twists (and more often than not rightly so), but she's still hardly the worst at meddling with the show. I'm aware that people get leading questions in the diary room, but it still mainly follows a defined path and maybe has a twist at the midway point or so. And more often than not it's the housemates that decide the course of the season.
E.g. a lot of the drama and action is quite organic and happens within the overall defined structure of the show. Other versions keep throwing shit at housemates and try to stir up drama that way. Channel 5 has been bad with it and all the "who said what" and "attribute these tweets to people", ITV needs task after tasks.. Seven needed a shit ton of twists to tell its story.
Also, as mentioned before: The US came up with a lot of casting twists that fit the "social experiment" angle of the show and were then adapted internationally because they fit the general idea of the show very well.
Now there are obviously moments where the US moved away from its roots. I've mentioned the campy editing before. You could certainly add all the strategy talk that overshadow the interpersonal conflicts. Part of it comes down to serving audience expectations (like so many other changes in the BB world), part of it is due to its scandals (like many of the changes in other countries, but as an example for the US: the US put more focus on comps and a cartoon-ish presentation after the racism on BB15). I would say that it changed a bit over the last two years again, where the storytelling became more character-driven and less task-driven again.
I could write for a lot longer.. (e.g. how the US is still thriving on the 'who needs to go' mechanics versus the 'who needs to stay' that we see internationally, which I think change the dynamics of the show... or how some international versions build seasons around Big Brother being a character or having an identity versus just being an observer like in the OG season...)... but the bf already made fun of me for almost writing a thesis on Big Brother and it's a thread on the house at Dreamworld, so I'll get to my final words:
All of this doesn't mean that the US is the superior version. It doesn't mean that all of the changes the show made internationally were bad. But it means that you see a lot more of the core ideas in the US than many other international seasons and it becomes clearer when you follow the evolution of the US format. You might also summarise it as "The US suffers from bad editing, not the format. A lot of international versions suffer from a crappy format, not so much from the editing".
And with those words: I'd like to apologise to anyone who has to scroll ages to get to the next post about the house.