It's been a slow march for years. For a long time I flew American, but as AA dehubbed STL and pulled back in NY and DL merged with NW and ramped up NY -- one day I was shocked that I was buying JFK -LHR on Delta instead of OW. I've got nothing against PHL, but it's never going to be my primary gateway. It's sad that AA is third in NY and STL now, but it's been a boon for B6 and WN.