I suspect that the deal had more facets than one. I speculate it went something like this:
1) McVay has not been quiet that he really likes Havrisik and had no intentions of losing him.
2) Havrisik was simply not performing well enough and the Rams had to do something.
3) Signing Crosby was legit. They feared Havrisik was regressing.
4) A kind of competition was created between Havrisik and Crosby and for one reason or another Havrisik really responded positively to it.
5) IN practice Crosby probably wasn't as sharp as they had hoped.
6) You can't have 2 kickers activated on game day, so a choice had to be made. McVay looked at the week's practice and chose Havrisik.
7) McVay's choice was vindicated. And perhaps Havrisik's issues were more about confidence and not really bearing down and focusing.
8) Crosby is a "last choice" or "emergency choice" when it comes to a Kicker, as can be seen by him being out of work. I suspect he's been around long enough to understand that.