IMO, Berniers price is a perfect storm of a couple different things driving it up:
-Past hype: He was taken 11OA and was looked at as the goalie of the future for 2 different clubs. Those different instances are easy to brush off for some. Obviously Quick beat him to the punch in LA, and (of course) the rebuilding Leafs would make any goalie look bad. In a way it kind of reminds of me of what I've seen/heard of Bill Ranford. Guy was pretty average to mediocre for the Oilers, but had a very clutch run in the '90 playoffs that won him a Conn Smythe and then he played excellent in the 1994 WC for Canada. Despite his not so great record outside those 2 events, it artificially gave him a boost in value and lead Boston, Washington and Tampa to give him a shot at their #1 job for the rest of the 90's despite not performing well. Even our own Ken Holland thought he was worthy as insurance for the failed attempt at a 3rd consecutive Cup in '99.
-It has to be difficult to gauge how much his salary should drop since on paper he hasn't necessarily been bad or mediocre since leaving Toronto where he was still making $4.15M a season
-In the previous three seasons, he seems to get hot just at the right time, so it's fresh on GM's minds when it comes time for his next job/contract:
Bernier seems to have two modes, inconsistently good to mediocre to not so great, or on a tear, without much in between. And he pretty consistently starts the year in good to bad to mediocre mode, then finishes the regular season on tear, before being bad in the playoffs if he plays there.
In 2015-16 before the Leafs traded Reimer to the Sharks, Bernier was 6-15-3 with a .895 SV%. After the trade: 6-6-0 with a .93
In 2016-17 he goes to the Ducks as an overpriced backup after the Leafs pick up Andersen. He starts the year a little better, but by New Years day, he's at .897. He plays better in January and February, before going on an absolute tear when Gibson goes down with an injury for the last week of February and all but one game in March.
Last season, he's at .893 by New Years eve, then goes lights out when Varlamov missed a month in January and early February. During that span he put up a 9 game win streak where he was .955. He then cooled off before dealing with various injuries of his. Eventually, Varlamov was injured again and missed the rest of the season and playoffs, where Bernier was anything but noteworthy.
And this year we've seen the same pattern. He's had some good games here and there and at New Year he's in that .89X range.