So it is true the A Level system makes it WAAAAAAY easier to compare students academically.
But again, you have to remember their system is way more concentrated, such that something like 18ish universities would all be within Oxbridge.
So I’m not going to bother doing this precisely, but there would be something like:
A: Harvard/MIT/Columbia/Chicago/Dartmouth/Hopkins/Northwestern/Vanderbilt/Rice
B: Yale/Stanford/Princeton/CalTech/Duke/Penn/Brown/Cornell/WUSTL
And one slot would be applying to either A or B, but not both, and the colleges within A and B would decide for you where exactly you ended up (although you could state a preference, your offer might come from a different college).
OK, now you have four more slots, and again each covers more ground. So it would be basically impossible for a high numbers kid to not have like 2 or 3 slots involve colleges which would almost surely admit that kid in the current US system too, using just numbers, as long as the kid was not also like a convicted serial killer.
So yes, their system has better numbers to use. But really, the same 4/5 type options exist in the US for high numbers kids. You just have to be open to those colleges.