The difference between Boom and Edwards is night and day. It's not even a question really. The only people who don't realize what an upgrade Edwards was in coming in for Boom are the most casual fans.
And re: Coach McVay talking Boom up... He does that with every player and that's today's NFL. It's irritating to me but there's a lot of benefits to doing it that way.
I remember people on Rams boards citing McVay's comments on Tavon Austin and interpreting them as "he's going to be a beast in this offense." Or that "they're not going to get rid of Tavon just see Coach's comments." Followed by Tavon being moved for a pack of chewing gum. I love Coach McVay but we can't tell a thing about individual players by his comments unless they're one of the guys who really is playing well. Gotta read between the lines with him.
Lastly I have to think that the Rams were aware Edwards was far better than Boom. They had to be. There is zero chance they missed that. So the conversation there IMO is about "why." Why would they reinstall Boom in his former position like that. Because he did not and would not win a competition against Edwards in any universe.