Cox isn't a producer of content; we simply distribute TV content produced by network and cable TV broadcasters. At this time, most of the 4K content available is offered by streaming services like Netflix and Amazon. Cox has the infrastructure in place to deliver 4K content and will continue to evaluate 4K content availability as 4K broadcasting grows.
With the exception of South Korea, nobody is in the UHD TV "game" because it will require a different tuner: ATSC 3.0. Although you already have a "4K" TV, you still only have an ATSC 1.0.
Remember the transition from analog to digital TV back in 2009 with convertor boxes? UHD broadcasts will undergo the same massive transition. You'll see lots of Public Service Announcements, Cox will issue new cable boxes and if you're receiving over-the-air broadcasts, you'll need a new antenna.
Even when the U.S. transitions to UHD TV broadcasts, your "4K" TV might be obsolete with its current technology. UHD is not just more pixels; it's a higher dynamic range, higher frame rate, deeper color bit rate, wider color gamut and more immersive audio. Netflix, Hulu and Amazon each have their own proprietary technology for their UHD content. Those technologies might be completely different from what broadcaster will use or what the FCC mandates.
Maybe you could update your firmware or maybe you can't. Who knows? With all the advanced capabilities of ATSC 3.0, you might need a different HDMI port. Again, who knows? When Cox gets ready to play, it'll be a whole different type of game.