I flew out with Wizz to Warsaw for a long weekend back in October just because I'd never have the chance to fly out of DSA again. The "Finningley Windmill" airside pub had already closed for good and some of the doors to the gates already had the gate numbers removed. It was fairly busy in first wave but would then sit empty for hours until the first TUI departures got back.
The only observation I would offer is that the totality of the Wizz and Thomson operations have been moved to nearby airports without much fuss whatsoever. That for me is a clue, the DSA experiment brought nothing that was really net new to the market, in later years it was all about fragmenting the existing market and grabbing a bigger share from competitors. I am a huge fan of competition but in this case, there was just not enough of any ROI.
The remaining bits and bobs have had to relocate across the country which leaves Vulcan XH558 in a very precarious place.