The problem is several fold here:
1. Goff can't throw the ball more than 20 yards. Now we have pieces that are designed to stretch the field, so is he the right QB for us?
2. All of those teams including the Rams with Goff had something going for them, they were really good teams without the QB. Those are hard to come by and the Lions haven't done that in 70 years. Do you expect them to figure it out now?
3. Even if the ones you listed, only one won a superbowl. The goal isn't making the playoffs or winning a couple games. Its about winning the big game. It's really really hard to do that without a top third QB. Do you think its prudent to keep Goff hope you have a good team then realize he can't get you over the hump therefore wasting those prime team years before the group gets dismantled.
4. You're counting on Goff playing like the last quarter, what if he plays like the first quarter?
5. While 27, Goff has been in the league for almost 7 years there is little likelyhood he improves on what he is.
Now, you could keep Goff and hope all those things become true or break the lions way or work to find an elite QB which makes everybody around him better. The second one seems slightly easier to find than building a crazy elite team Rob Johnson style.