The article doesn’t explicitly state it but heavily implies “the Xbox series S is too weak for modern titles”. The optimization is necessary because it’s weak as fuck. It’s very much the same as optimizing for a PC, with the additional constraint that they need to artificially dial down the experience on other consoles, too, due to contract stipulations that prevents them from “giving an edge” to a competing product. The problem is not that it’s different from optimizing for PC, the problem is that it’s “optimizing for a PC that is in principle too weak to handle the load”.