Rex vs Vincent is not a realistic comparison.
Yes they both run/ran Saabs, but Rex invest a reasonable amount of money in ground equipment for their RPT network. Every port in North Queensland has ground power and air conditioning units. From personal experience it keeps the cabin cool and the passengers happy. I actually found the A/C in the Saab better than the Dash 8 on account of the two A/C packs once the engines where running. Not sure what the Bras has.
I don’t think Rex will build a network specifically to take down another competitor. They’ve never done this anywhere else on their network. If the NT government and the various communities are open to Rex starting service (reasonable access charges, etc), then I’d put my money on them expanding up there eventually. When Skytrans went under in NQ, some of the councils/communities were openly hostile to Rex flying to their towns. Hence they just walked away and chased work elsewhere in Australia (WA).