It is, in the sense that it's not just Trotz but Korn and Grieco. Great goalie coaches, like the Rangers also have, can turn good into excellent. As good as Shesterkin is, others could be just as good there. And have been.
No, thats not true.
Don't give goalie coaches and head coaches too much credit. There are a pool of goalies that range between good AHL goalies, to some range of back up level goalies, to low/mid-end starters. The head coaches, systems, defenses, goalie coaches make the difference for players in that range. Those are the players who this goalies are voodoo narrative might apply to.
If you look at the guys that end up winning the Vezina. Go back about 10 years. In the last 10 years, none of those guys are system goalies that a goalie coach made magic out of. Those guys are all Hall of Famers, close to Hall of Famers, or players who were starters pretty much their whole career and in their prime were among the best in the league. Those guys accomplished what they did mostly due to their talent. And thats 9 players, so while it's true that goalies often don't pile up the career awards that skaters due, it's not that the best ones are inconsistent or voodoo or any of these stupid narratives that aren't based on reality.
The nature of the position means that goalies have shorter primes. They start in the NHL later, they are more susceptible to the types of injuries that would strip them of their talent, and they are easier to acquire. But this stuff is already accounted for in these discussions. There is not a suggestion to pay them until they are 39. It's accounted for that these guys usually have a shorter window than skaters. And their shorter window doesn't mean that there's no distinguishable difference between the 3rd best goalie in the league and the 33rd. The best goalies in the league absolutely are worth the contracts they get, and they contribute as much to success as skaters.