Geez, this place sometimes...!
Yes, Koskinen has had a relatively poor season. Yes, Smith is clearly better right now.
No, the club didn't suddenly decide to buy out Koskinen after one utterly meaningless game when the skaters managed 1 goal against a sixth-place team.
Goalies like Brayden Holtby (recent Cup winner), Devan Dubnyk, Freddie Anderson, Brian Elliot (former Jennings winner), and Matt Murray (recent Cup winner) all had worse save percentages than Koskinen this season.
Had Koskinen not been over-played so much in January, I'm sure his save percentage would be just a tad higher, and he'd be up there with Khudobin, Halak, and Bobrobsky, right in the center of the NHL pack, which is what I'd expect from the guy who is effectively the back-up goalie.
(It's also quite reasonable to expect Koskinen to get back to 2019-20's form next season. People do bounce back.)
Oilers' fandom seems to have collectively decided Koskinen is our mortal enemy because Chiarelli overpaid him.
I'm generally a Koskinen supporter for reasons like you say. I do think there is too much focus on the salary from us fans. I'm not faulting any of us for understanding the GM side, and that's part of the appeal of sports, but we should also be able to file that away at some point and get the most with what we have instead of constantly including salary concerns, or who that player was traded for. Getting hung up on Koskinen's salary is just as bad as constantly bringing up Hall when talking about Larsson.
Overall, imo it's better to be biased in favor of Koskinen because he is here so we should make the most of him. Buying him out adds a cap hit this year as well as the next. Until recently I was adament that replacing him wouldn't be worth it in the end. For all his faults, as a back up he'd be okay, and there is potential for him to get hot and be more than that. Overpaid, but useful
But things have changed. First off, this is the offseason to get our goalie of the future. Driedger, Ullmark, trade option, and on top of that expansion might knock someone loose. Also, it is looking more and more like maybe Smith could have yet another season in him. That makes 2 goalies.
Buying out Koskinen makes sense if he doesn't have a role here. Also, I do agree with you that he is better than what we've seen at the start and end of this season. However, it feels like the relationship between him, the team, and the fans has soured. Perhaps the right time to move on, for everyone.
But like with other situations, playoffs can change a lot. Our team does not want to give RNH the money he wants, and so as of today it looks like he's out of here, but the playoffs can change lots. With Koskinen however, it's unlikely he gets that opportunity. Maybe Tippett goes with Stalock now, and of course Smith will play as many games as he can handle regardless.