Docsis 3.1 Upload Speed

Will Cox ever be able to take full advantage of Docsis 3.1 in terms of Upload speed? Will we ever have symmetrical? I'm seriously considering basing my home purchase on the availability of fiber internet (which is also abysmal in the Phoenix, AZ area between both providers) because I have serious doubts Cox will ever deliver. My internet bill (gigablast and unlimited data) is my 2nd highest monthly expense and I just don't feel I get my money's worth.