@HappilyContentTheseDays you make good points and I agree.
The top girls' boarding are seeing an influx from Asia, Europe, etc. There's a way to game the system to get to the Ivy Leagues etc, you need to be in the top 5% or so, do 3 A levels where one is effectively a language that's mother tongue, although you're not that nationality & it's far from obvious, and you're hugely advantaged. Not confined to languages. Serious thought goes into it all. All perfectly within the 'rules'.
You end up with a smart school name on your CV, a brand, and this is what's important as some see it. You have that in Asia currently. It's a useful, first stepping stone to a stellar career and life. You have a system where there are 30/40 in the class but all the learning goes on with a guru in the enrichment centre after school finishes at lunchtime and is topped up with tuition etc. So it makes sense this model will transfer to the UK if that's your experience.
Then lots of focus on super curricular over the two years and money helps hugely here. That sort of thing. Not to mention most of the Asian pupils having tuition in the holidays to mean they work a year ahead. Residential tutors are common in hols and additionally, tutoring all week very common, online.
Some also do SAT and ACT etc prep from age of 12 or so, weekly. They get fast and quick. A piece of cake when the time comes, they are ahead of the game, coupled with the above.
I've noticed where in past the wealthy internationals wouldn't be at a particular advantage, now the top schools are being increasingly swayed and influenced. I believe there was a radio interview some time back with previous Eton head, Tony Little. He said he would seriously consider one boy over another re: entering Eton, IF academically up to scratch, or close, if a parent offered extra cash, or something like that from memory. His reasoning, as I recall, was that this would help him offer more places to the talented via bursaries etc. He explained he would consider this if a prospective pupil didn't have the requisite smarts to flourish.
He who pays the piper calls the tune. Things are being accommodated that might not have been previously. What I have seen is that local, UK pupils often feel the pressure, they can feel dim when smart, and the teachers are not always aware that new content will be effectively revision for some and new material for others. This can lead to a troubling toxic competitive atmosphere. I think this is growing. Not everyone will be robust enough to be equipped to cope with a dog-eat-dog environment.
I think international pupils have to pay double at Millfield and Oundle have taken donations from parents to pay for new facilities. Whilst objectively a lot and out of the reach of most, 40k PA boarding school fees are just not enough to run the schools any longer IMO. The model doesn't work in many cases for lots of reasons.