Why is London necessarily better?!
Again, and this only applies to criminal/mixed practice not commercial/chancery, but barristers tend to get much more experience much quicker out of London than in London, particularly trial experience, and so their careers tend to progress quicker than non-Londoners who can spend years doing basic stuff. Plus the pay is actually often better out of London (especially when one takes into account ridiculous travel costs & living costs!)
And most importantly of all, if you are taken on as a pupil out of London usually that is because they want to keep you and help you develop, and unless you completely mess it up they take you on as a tenant - in London, having got that pupillage, only 1 of the 4 will be taken on (for info on this read the fabulous blog by Baby Barista - babybarista.blogspot.com) - most applicants know this so, if there were no other factors e.g. friends/family etc. would probably choose a non-London set!
"good" people apply everywhere, not just London so no, I wouldn't say that better applicants go to London therefore it is easier to get one outside of it, quite the contrary I know Oxbridge graduates who refuse(d) to apply to London sets.
So sorry, you're wrong - when all the applicants have similar CVs (and often duplicate as we can apply to more than one) it seems logical that more applicants DOES mean harder. Those figures are based on what chambers have told me during/after interviews so are accurate and not guesses, as other figures on this board might be!