I can’t chalk this up to a case of circumstances only.
He’s the only coach in St Louis history to bring a SC championship to the city.
It could be argued that they had better opportunities and teams to do it and yet no one delivered. He also had the team in the playoffs 4 of the 5 full seasons he was the HC.
Something that Scotty Bowman, Quenneville, Hitchcock, Keenan, Al Arbour, Emile Francis, Jacques Martin & Demers, Brian Sutter and many others couldn’t do in their 50+ years of existence at the time.
Armstrong‘s roster stupidity in losing Dunn, especially Pieterangelo, Schwartz and others has a lot to do with this.