Ughhh, most cities have one airport, whether they are in Europe or the US, certain larger ones have two, occasionally a third. That is unless you partake in a Ryanair like subterfuge where airports up to 200 km away from a city are labelled as that cities airport? These types of airports exist in North America as well, but no one has ever tried to say that other southern Californian airports are in fact Los Angeles, nor that Newburgh is New York City, etc.
As far as the premise of the article goes, I don't know. If I just happen to need to commute between London and Torp, things have never been better/cheaper than they are now. Not so great if I need to get between London and Istanbul for example. Furthermore just looking at the cheapest possible fares is a bit ridiculous no matter which side you look from, and some sort of median fare would have to be examined which also took into account add-ons and fees across the board.
Lastly KLM, and we have discussed this several times, we all know how much you love to bash US "zombie" airlines (as you put it), and you talk with great pride at how Swissair was allowed to collapse (but you then of course ignore the fact that the Swiss government put a gun to everyone's head to financially support a successor, to throw all the good assets into Crossair, name is SWISS and even when that failed make a political decision to let LH have it for a Euro. SN Brussels is almost the same story, and we can speak about in the last decade alone Aer Lingus, Iberia, Olympic and Alitalia multiple times as well as others, and I am not even delving into the 90's where AF alone received more subsidy than all US carriers received for 9/11 alone.