You make my point for me.
Injuries can deplete otherwise very good teams and injuries at key positions especially.
Look what happened when Gurley got the injury that left him never the same again. It affected the Rams deeply.
The Niners can't seem to stay healthy, and so they're a .500 team. Saints 5-7. Fully healthy these teams are much better than those records.
You can blow off the Rams injuries and constant churn of OCs and DC's and losses to FA, etc., if you want to. You can dismiss losing a rising star RB in Akers or a #1 WR in Woods. But that's not realistic imo. There aren't guys just standing around ready to step in at their level.
The Rams have to rebuild the coaching staff every year. And, they have to find replacements for really good players that get big bucks contracts in FA every year. Usually 2 or more.
This isn't "next man up". It is very hard to do and few teams have been able to overcome it the way Snead and McVay have. So let's give some credit where it's due and not just find stuff to criticize.... and always after the fact.