If you want to rationalize the loss of three receivers on the roster, all of them ahead of the guys on the practice squad, all of whom had talent and playmaking ability, all of whom practiced and trained with the team, go right ahead. And be as non-linear as you want. You can hypothesize better potential performance from the practice squad all day long. The reality is the Rams in a week or so just lost an enormous amount of depth at wr.
No one to my knowledge has claimed that there is anyone who could replace Kupp. But if we lose Kupp or Woods, or even Jefferson, I would have preferred for the Rams to have Harris or Jackson, or yes even Atwell, as options to go to in some fashion or for some plays. We drafted/signed them precisely to have more fire power and potential explosive plays at wr. Last year we didn't have it. And when Kupp went down we struggled to make plays downfield against Green Bay.
Obviously we didn't see Harris much at wr. But Harris is an elite athlete who was consistently making pro level receptions downfield in camp especially on routes where his speed and/or height make him a problem to defend. Imo it would have been better if McVay had played him more. But that doesn't mean he wasn't learning the offense or couldn't play. Didn't see much of Jackson either though he showed early in the season he could still break open deep routes and make big plays.
Think we might have used those guys in games, including playoffs, if Kupp or Woods went down? Imo yes, we would have. They're playmakers. Will someone from the practice squad be able to potentially make plays of the same calibre? I doubt it.
I would be happy to be wrong but imo our passing game is now at much greater risk of taking a big hit from any further injuries.