"Anyway, running a country on eloquence alone hasn’t worked out disastrously – or at least not yet" Good grades are certainly not enough, but they are almost always required. Oxbridge only invites the best students to interview, and even the top 5 most academically competitive schools in the UK struggle to send more than a third of their students to Oxford or Cambridge in a good year.
"Anyway, running a country on eloquence alone hasn’t worked out disastrously – or at least not yet" The largest empire the world has ever seen whittled down to its homeland, a naval base in the med, and some godforsaken islands in the south atlantic. I'd call that pretty disastrous. It'll only get worse. In an increasingly technical world, the brits have the wrong culture of Snow's two cutures running the show.
Actually, I would count the graceful degradation of the British empire (i.e without the entire country going to hell) as quite an achievement - particularly considering it happened with a surprisingly low level of long-term resentment incurred from the former colonies. Further, the claim that it was due to poor management more than, for example, two ludicrously expensive wars, is more than a touch disingenuous.
I suppose one could argue that the first of those wars was rather a waste, but Britain was hardly the only country to be affected by that particular insanity.