This is indeed a world wide problem. In Finland, Malmi (another city centre airport) was due to close in December, but reportedly gasps on for a year or two more, though the operator Finnair has quit and it's to be operated by the city council directly in the meantime.
In UK, Wellesbourne hangs by the slender thread of Compulsory Purchase threatened by the local council in the face of many local property owners who stand to make a (large) financial gain if it closes. I'm not confident of a good outcome there.
Santa Monica is not only convenient for an annual industry convention that I attend at Century City, but also for the President who based his helicopter entourage there during the same week and closed down my planned side trip to Catalina Island with his TFR!
So that's three airports frequented by me alone that are on life support. Against that I can set the brand new Saint George (Utah) at which I was the first 'international' arrival, but not many more new airports. Even Saint George replaced a much more convenient downtown airport, now closed but still tantalisingly visible, like Filton or Sheffield City. I suppose Inishboffin off the Connemara coast would count if it ever opened to traffic, and of course the new airport at St Helena definitely counts but is a tiny bit outside my range, so it's not all bad....