I wouldn't worry about that for at least another 8-10 years. Remember that ATSC 3.0 will have to be formally adopted by Congress before DTV has any timetable for going away.I'll have to see what they come up with for ATSC 3.0 USB tuners over at Hauppauge in the future.
I don't expect much unique to ATSC 3.0 (UHD, HGR, WCG) before the bandwidth used by DTV is freed up. Having to share the repacked airwaves with such a bed hog is no picnic.
For those who like to talk about how much progress South Korea has made towards ATSC 3.0, I note that South Korea is a bit larger than the state of Indiana and has more than two and a half times the population of the state of New York.