Lions go 2-0, Bears win next week and lose to the Niners, Packers lose to the Ravens, and the Lions will be playing for the division against Chicago. In a scenario where a loss likely eliminates them.
If they miss the playoffs, and I still don't think they will, it's not a loss to the Rams that will cost them. It's the inexplicable loss to the Vikings who started the worst QB in the NFL. It's being 1-3 in the division.
I don't understand not trying an onside kick when your defense has shown zero ability to make a crucial stop. You're just hoping for a lucky break, and if you're hoping for a lucky break, hope for it on an onside kick.