I'll be honest, one person certainly lowers a team's performance, but one person can't change the outcome.
Football is a team game, and placing all your trust in one player is like shifting responsibility to just one person. I don't agree with this vision of the game.
Stars make the difference, but let's remember that we're all important; no one is indispensable. Atalanta just needs to find a good goalscorer, perhaps one better than Retegui. There are many young talents yet to be discovered, and there always will be, we just need to give them opportunities.
This is why most teams struggles a lot anytime that their game changer is not playing well or got injured. Am equally not a big fan of depending on a single player because once they have been held down, the team will be unable to perform as they should have done.
And for Atalanta to get back to the strong team that they are known to be, they have to add more firepower to this team and play collectively, than depending on a single player to do the magic, with that they might even perform better than what they did last season. As for the case of ademola lookman, I don't really know how his relations with the team is, if he will be reintegrated into the team or not, since his plan on moving away didn't materialize, but since the transfer market is closed, everyone needs to keep their grievance aside and work for the betterment of the team, he has to be brought back into the team because they needs his creativity.
Atalanta is beginning to degrade out of the team it used to be and this is majorly due to the way they built the game initially around Ademola Lookman the previous year. This is not to justify their dwindling stance but to urge the team to look inwardly, in as much as Ademola Lookman could not secure a move, he should be integrated into the team while coaching up his replacement. The team misunderstanding is also influencing his output in this ongoing international game. You can tell his unsettled heart from his countenance during the break. If the team reintegrate him, it would be more profitable for them when the transfer window opens in January. But leaving him out of the games would cause both economic waste and self degradation.