You may have the bandwidth, but the cost of bandwidth will increase for the service providers like Netflix. That's the main problem today. It's too expensive for the stream providers to fully switch to 4K streaming. The cost of bandwidth will at least double for the providers, and unless they increase their prices 4K will not be available for mainstream usage.
Theoretically but like the the Mac Pro, very doubtful if that's a practical likelihood. 4K port is HDMI 2.0, such a shame they're not looking forwards . . . .
Here's how it will likely work. 1080p model this year while 4k is still not relevant. I've casually watched all the 4k content Netflix has to offer in under 3 weeks. There is nothing. 4k TV is hilariously embarrassing, it's just pretty pictures of the ocean and sun rises to utilize the technology, there is no "meat"...
4k model released in a year or two as it gains popularity
1080p model and 4k models sold side by side with the 1080p model obviously being cheaper.
It doesn't make sense from a business perspective to push an update to make it 4k (not that it has the hardware to support it anyway).