McVay has a long view with this roster. He wants to get to the playoffs with his receiving threats healthy so he can win it all. It's not gonna be easy either. Kupp already is doing what he does which is almost force the QB to feature him by being open. But both him and Jackson need to be healthy going in.
Your point is valid. McVay is the coach who went and added Jackson. If you reloaded the offseason right now after seeing him in this offense there would be competition for his services. So to think he doesn't know what he can do, after the guy BBQ'd our secondary all through camp, is ridiculous.
I'll say again that having Kupp in 2018 for the Super Bowl = Rams win the championship. Having him even last year vs Green Bay maybe we win and go further. So the guy understands that he needs this roster healthy going in and knows that is the most important thing because this team is going to be in the playoffs even if they sat Kupp the rest of the schedule.