All goalies are a flash in the pan.
Unless you're talking about one of the top, top goalies in NHL history, most goaltender's resumes tend to be built on 2-4 distinct seasons.
Even Pekka Rinne, who had an excellent career, had as many negative GSAA seasons as positive ones.
I think Swayman is pretty good and a decent bet to give you some good years, but unless he ends up being a first-ballot Hall of Famer, he probably ends up having like 3 great years, 4 ok years, and 4 bad years. That's most goaltending careers.
I think Rinne was the one of the most interesting careers of that generation of goalies. He had a real peak, valley, peak, valley type of career.
Was a really good, probably elite goalie until he was around 30., He may have had a ho-hum season or two early on when he was young, without having his numbers in front of me.
Then he goes and has a couple of pretty poor seasons in a row to start his 30s. I think those coincided with his hip issues. Then he has a comeback season in 14-15 (I think that was the year?) and is a Vezina finalist. Then he follows that up with yet another mediocre season in 15-16. I remember thinking he was one of the more overrated goalies in the league around that point, as most people were just ranking him high on reputation, a reputation that seemed pretty dated by that point.
But then he went on to have 3 pretty good seasons in a row after that, which included his only Vezina win when he was 35.
He fell off after that stretch, but he was old by that point.
After the late career resurrection I remember people like being like ''You said he was bad tho!'' well he was, but then he resurrected from the dead and a had a consistently good 3 year stretch after a pretty poor 3 out of 4 year stretch prior.