the idea that because bluetooth headphones exist means the jack shouldnt exist is not fair -- there are plenty of reasons the jack is plenty useful to plenty enough people
the only excuse I can see to remove the jack is that when you sell a billion devices and the little jack costs a buck a device you just made yourself a billion dollars for nothing. oh and now you can sell dongles that cost $1 a pop to make for $10 a pop and you make yourself 10 billion