Backstrom was their best player until he got the surgery. Oshie had a higher PPG last year than Mangiapane this year and their cap hit is virtually identical. Strome was a UFA for anyone to sign. Chychrun was traded for Jensen+ who had a difference of $500k in cap hit.
Dubois has been unreal for them and wouldn’t have been possible without the Backstrom LTIR. But if Backstrom wasn’t hurt/LTIR possible he’s likely still a top 6 center. Better than Dubois right now? Probably not. But if you’re assuming he didn’t have the injury (so he wouldn’t have been LTIR possible), his overall game was aging better than Ovechkin at the time who is still extremely productive. The other moves are all still possible, save the Mangiapane on line 3/4 for Oshie swap which isn’t a difference maker. The Thompson, Lindgren, Sandin, TVR, Raddysh, and Duhaime deals could have been made by almost every other team. Other than that, it’s been Protas and McMichael’s development. Calling them lucky is just an extreme cope/cop out.