The Rams will probably stay in the mix for OBJ. He wants to come back to McVay and the Rams. It's not totally in the Rams control. Atwell, Benny Skow and Harris will get chances to show off what they have. You also have the progress of Jefferson and unforeseen injuries. I doubt Atwell by himself can take OBJ out of the picture. It's always about weighing the options. The Rams could go for a defensive player if needed and one they like becomes available. Snead and McVay will make moves they think are best. All options will be explored.
Imo Rams want OBJ back and, assuming his knee is good and they can agree on terms, will sign him. At the moment we are just in the expected scenario of both sides waiting to confirm progress on OBJ's knee. Development of other receivers is a big positive, but not the decisive factor in the OBJ equation.
The big reason: McVay wants another title. This year. He saw what OBJ could do in the playoffs. As another poster pointed out, and McVay surely knows, Kupp, Robinson, and OBJ together would be unstoppable in the postseason. McVay will get OBJ back if he possibly can.
The outlier variable imo is not other receivers but a possible Von Miller style defection with OBJ going for a longer contract with more guaranteed bucks over time. Rams may offer a shorter term front loaded contract. Say, three years. OBJ will have to see if he can get more years elsewhere. If so, will he prefer a longer contract in Siberia to winning another Super Bowl.