A lot more is being done than simply stopping the DNT at US-380. In the near future the DNT will be extended up to FM-428. A second pair of frontage road lanes was added to Dallas Parkway up to FM-428 a few years ago. Work is underway to extend Dallas Parkway
and future DNT ROW from FM-428 up to FM-121. From there the Grayson County Toll Road would take over the rest of the way to US-75 in Denison. The DNT probably would have been built past FM-428 already if not for the need to add more lanes farther South.
Construction on the Grayson County Toll Road from Gunter on Northward could potentially go much faster than DNT projects since there isn't as much residential and commercial development in the highway's path
-at least for the time being. To save money and secure ROW faster they could just build the highway initially as a limited access Super 2 and then add in the second roadway later.
TxDOT will look at expanding 75 to 6 lanes to the Red River once traffic justifies it.
It doesn't already? There's a ridiculous amount of semi truck traffic on that highway. The Choctaw Casino & Resort South of Durant is drawing more traffic. There is been a hell of a lot of expansion at that casino complex in the last few years.