In all cities that have replaced their airport with a newer/larger one, they have ended up with the new facility further out than the old smaller one. It is not a phenomena, if you think about it, it would be expected to happen this way.

Most developers of such, especially politicians, think that every airline will only want to serve their all-new, all-wonderful, (high fees, less accessible) eighth wonder of the world. Of course airline executives find that the passengers, who end up paying the bills for it all, do not feel this way. It is an approach that worked in regulated days with the legacy carriers but new entrants to the market look at these underused, low fee, more accessible airports and just give the market what it wants.

London City is the only example I can think of where a totally new facility has been built from scratch closer to the city than the existing main airport. The others have always been there for longer.