There is simply no realistic scenario that benefits the Lions as much as Jared Goff regaining some to all of his form. Regardless of one’s feelings on whether or not he can accomplish this, I think this can be fairly universally agreed upon.
To that end, the risk / reward scenario of sticking with him for 2022 is strongly in favor of going into the season with him as the starter.
Doing this allows the team to spend all of its resources improving the rest of the team. Getting a legit WR corps and adding key pieces to the defense needs to be done one way or the other, so doing them now makes sense.
Best case scenario, between having an actual WR corps, a healthy line, and a supportive running game, Goff looks like the Pro Bowler he was in LA. No wasted picks or money on another QB, and the team is ready to go after it hard.
Worst case scenario, Goff shits his britches again and is clearly the problem. So you spend resources in the 2023 draft to go get your quarterback. That doesn’t set you back any further than spending resources on QB in 2022 and then having to address the other parts you skipped in 2023.
Anywhere in between? You’ve got options. You can win games and establish a culture if Goff ends up being of the Alex Smith / Kirk Cousins type. The team can call their shot and make a move when it suits them rather than being forced into something.
Unless Holmbell has some proprietary knowledge that Goff is unfixable, I suspect this is the tack they’ll take.