Only in politics could you get someone appointed to a top job with zero experience. Quite often, you hear laments about how the UK has a defence secretary who has never fought, a Chancellor who has never run anything bigger than a raffle, a health secretary who has only ever been a user of the NHS. In America, by contrast, the president gets to pick who he likes — so you can have genuine experts. But there are exceptions to this rule.
One is John Nash, an entrepreneur and venture capitalist who runs a charity which has set up a very successful school. He has just been appointed schools minister: a round peg in a round hole.
And Barack Obama has shown less interest in outside experience than any modern president (as the above graph from JP Morgan shows). So yes, our systems are different. But there is considerable latitude — for good, and for ill.