Centralized miners suffer much lower orphan blocks if the orphan block rate is macroscopic and driven by actual propagation time. If you're in a regime where one would want to do something to lower their orphan rate, the optimal income maximizing strategy is to centralize, not to reduce sizes.

Though at least fundamentally we know there there is no need for the orphan rate to increase proportional to block-size, if miners use more efficient relaying mechanisms that take advantage of the transactions having been already sent in advance.