Gotta say SF played it smart. They publicly praised the kid, talked about how they loved having him on the team, he was a valuable player. etc. Made sure not to devalue him. Then they got rid of him and got a reasonable pick.
Of course, drafting him in the first place was a whiff, but at least they eventually got something.
They could have been the Colts, made it quite obvious that they don’t want a player like Jonathan Taylor, and then start asking for offers.
They did well by not worrying about the sunk cost, and as you say, not talking smack about him. But everyone knew they wanted to offload him, so they had no bargaining power at this point in the season. I think they could have gotten better than a 4th rounder if they’d waited a few weeks for another team to have more pressing QB needs.
That’s entirely possible.
The only reason that’s the case is because they picked Purdy in the 7th. That argues in favor of drafting QBs in every draft even if late. Many teams would have grabbed a special teamer or project OL with that pick knowing they had both Garoppolo and Lance on the roster. You need to constantly be hedging your bets at QB even when you think you have a guy.
Covid was when he was at college, and dispite that Lance opted to to go enter the 2021 draft after a redshirt year a fukll season and a season with 1 game due to covid. For comparison to his 318 pass attempts at college Lawence had 1138, Wilson had 873 and Fields 618.
With such little tape on him the 49ers bet the farm on him they were not even desperate for a QB as the they had Jimmy G. Yes injuries had played a part but if they though Lance was their QBOTF they would have kept him as starter in his rookie season when Garrapollo came back from injury. By bringing in Darnold at a time when it was not clear whether Purdy would start the season it was clear he was trusted even as a backup.
As roster cutdowns begin, it’s looking like (barring a free-agent pickup) the Packers will be going with a new kicker and a new punter, neither of whom have never played in a regular-season NFL game.
The Cardinals are keeping QB Kyler Murray on the Physically Unable to Perform list for now, and have cut veteran QB Colt McCoy.
Murray won’t be eligible to be activated from the PUP list until after at least the first four games of the season, meaning that, as it stands now, the Cardinals will enter the season with either journeyman Joshua Dobbs (whom they obtained from the Browns on Thursday) or fifth-round rookie Clayton Tune as their starting quarterback.
Tanking for Caleb Williams?
Fail-eb for Caleb?
Cock-Up for Caleb
(British slang)
Meanwhile, the Chiefs are apparently going to see if they really need a defense. Chris Jones is apparently willing to sit out 8 weeks to get the contract he thinks he deserves (and probably does), and management is apparently willing to let him.
Patriots have dropped all QBs on the roster except starter Mac Jones, eliminating any hint of a QB controversy and handing the reins to Jones definitively. All the press here pre-cuts was that Bailey Zappe was a lock for backup QB and that undrafted Malik Cunningham might even make the roster as a gadget QB and occasional receiver. Nope! Both were released. (Though I am sure the Pats are hoping at least one of them won’t get snagged up and can be signed to the practice squad.)
Speculation is that the Pats will now seek to bring on a veteran back-up QB who will not be expected to compete for the starting job. But then, the previous speculation was, as noted above, dead wrong, so who knows!
The Patriots released quarterbacks Bailey Zappe and Malik Cunningham, leaving starter Mac Jones as the only qb on the roster. Undoubtedly they have a plan to sign somebody else before Sunday, but, man, this is a strange move.
ETA: Ninja’ed by @ShadowFacts!
Haha! Ninja’d, sucka! 
Very strange.
If I had to guess, I’d say they decided to roll the dice on a backup QB - gambling on getting Zappe back after final cutdowns and waiver wire pickups. And if they can’t get Zappe back, not sweating it too much on picking up a veteran backup from somewhere.
They’ll bring Zappe back or perhaps coax Jeff George out of retirement. 
Carson Wentz is still very much available.
Will Grier szn.
And in a surprise to very few, both Zappe and Cunningham cleared waivers and have reportedly signed on to the Patriots’ practice squad