I don't pretend to watch all of Gibson's games, but the reality is when you're a .904 goalie, there's likely a bunch of softies in there.
Gibson has been a career .912 goalie in the playoffs, but all of his playoff numbers have occurred in years when he was a .920+ goalie in the regular season.
With respect to the bolded, you're correct. But John Gibson is not an elite goalie, or at the very least, has not been anywhere near one over the last 3 years.
I'm not saying that Gibson at $6.4m is negative value or anything like that, I just think that a good team, who needs a goalie is going to have to take a fairly big leap of faith in him needing a change of scenery to believe that he's their guy in net, and worth committing #1 money to.
There's lots of bad teams who will happily acquire him to stabilize the goaltending position, get some upside, but bad teams are generally not going to give up big hauls of futures.