Murray was absolutely nails before his injuries, he was a high-pedigree goalie and a stud-in-waiting for anyone that was paying attention, this would be like being suprised if Askarov of Wallstedt debuted hot. MAF is a roller coaster, sure, but no one would say he wasn't a top-10 goalie.
Holtby was absolutely an elite goalie.
Binnington was lightning in a bottle resurrecting a Blues team that was dead last. That was a prayer, not a plan.
Vas is a top goalie.
Kuemper's save percentage is good for 20th all time and 6th amongst active goalies--he's not a hall of famer but when he's healthy he's a stud and underrated.
Adin Hill, like Binnington, wasn't a plan, he was 4th man up, 5th if you count Quick's attempt.
All of those Cup teams entered those seasons with either an elite/top tier goalie or had one find lightning in a bottle after everything went wrong--not one of them PLANNED on having a mediocre goalie help them to the promised land, which is different between them and Rob Blake's lottery plan of trying out three scratchers and praying. The Blues had missed the playoffs the previous year and were a strong team but a 'surprise' champion and they started the season with Jake Allen. Vegas was a true contender who was entering the season with Lehner and Broissoit and when they were hurt they had a stud prospect in Thompson...it was only when he got hurt that Hill came in.
the biggest myth in the league is the 'you just need league average goaltending' thing that's been oddly persistent since 2010 when it's clearly the exception to the rule AND the exceptions weren't planned like "this is our guy" they were accidents teams fell into after their initial plans failed. And no one but Blake has gone out and gotten THREE .900 goaltenders on a budget and marched them out as a contender. When you're playing the best and the best and your teams are roughly evenly matched a goalie on fire can make a difference and you would think watching Quick bail us out in big moments for years would solidify that opinion. "just league average" goaltending is fine for one-off non-conference games in december but no one on earth is saying "yeah I'm so glad I have Dave Rittich for 7 games vs. Connor McDavid."