I think a lot of us thought that the Trey Lance selection was solid, or at least better than some other choices. I was definitely excited by the possibility of what he could bring to the team. You can argue that they gave up too much to get him, but he showed all the tools that would likely make him a pretty good QB. And if you already have a standout team you can make those kinds of gambles.
But for various reasons, including major injury, it didn't work out like everyone hoped and another guy you drafted for cheap appears to be the real deal.
Yes, there is opportunity cost with the lost picks, and that sucks. But if Purdy continues to perform and grow and Darnold is your choice at backup (and he appears to be solid), you do what you need to do to keep moving forward. Does it really matter where guys were picked as long as you get solid performers?
There's commentators out there saying that Trey Lance didn't fail, the team failed. I don't know that I agree with that. Teams don't "fail" because a player gets seriously injured. Teams don't "fail" because they drafted two promising QB in the same draft class and one appears to have panned out. The average length of an NFL player's career is 3 years, which is about where we are with Lance and, frankly, only a handful of actual games played to show for it. We'll see how Lance does in the future, and I wish him well, but this team has to keep moving forward. That's what they are doing now.
Teams make mistakes in drafting / sometimes draft promising players that just can't get the job done. It happens all the time in every sport (as Kings fans, we should be used to this). It sucks, but all you can do is try to learn from it for the next year. Meanwhile, I'm not going to dwell on it and look forward to hopefully another run towards appearing in the Super Bowl with a stacked team and one of the best coaches in the league.
Now, I will say that the 49ers seem to have a history of QB controversy over the years and that isn't the best approach. They also bungled the messaging and timing in numerous ways. That's another thing they need to work on getting better at.