you can look at any GM who has had a long tenure with any team and look at the trades they made and say "Look at all the players they could have had if they didnt make trades."
Firstly, Milbury makes trades to improve his team: Hamrlik, Peca, Yashin, Osgood, Parrish - all those players produced before they came to the islanders (and even when they plyed for the islanders to some extent) No GM in the league can possibly predict when a player is on the downside of his career. Great example Pierre lacroix: is he not one of the top 3 best GM's in the league? Did he not sign Teemu Selanne, the same Teemu Selanne who was pretty fair last year, but blew this year?
Same with Yashin, Yashin was incredible when he was signed, definetly worth the money and definetly worth signing, any team woulda gotten him for some unproven talent.
Also, his team might not seem so great on paper but they still made the playoffs there are lots of GM's in the league with bigger budgets that are similiar or even worse.
Those teams include:
Vancouver: similiar budget, similiar playoff history, yeh better players but end result is the same
Boston: similiar budget, similiar playoff history, better players, similiar outcome
Chicago: Great playoff city, GM blows
LA: Similiar budget, similiar playoff history, after all the injuries team seems similair lol
Rangers: bigger budget..horrible predictors of skill
etc...theres plenty of GM's that are worse we can start topics about them=D