I am not going to be drawn into comparing the merits of each first Vuelta ride for these guys, but just in terms if communication from the respective teams, IIRC all 3 others were considered big future hopes, while pre-2021 season the talk of Vingegaard playing a big role in GTs was rather muted.
I could be misremembering things, but the original plan was for Kruijswijk and Kuss to be the main Vuelta guys.
Sure, he was never going to be second in line at the Vuelta with it being his first GT, but instead have a role like Kuss had in 2018.
I was expecting him to reach a very high level at some point if he had the required luck, but I never thought it would happen so soon and neither did the team apparently. Actually the results he got before the Tour were better than what I had expected for this year, given that he didn't improve more during last season.
So while it's definitely a surprise to me that he's now second in the Tour, just like it was with Quintana back in the day, it's not as surprising that he was potentially able to reach it during his career, if everything were to fall into place. His injuries in 2017 and '18 meant he never got a chance to ride for GC in the Tour l'Avenir. I obviously don't know how well he could have done there, but if he had finished in the top 5 or even better in 2018 where Pogacar won, I'm sure a lot more people would have had him on their radar.