No, I don't think it's realistic to expect reviewers to "maintain" their reviews over time. The few outlets that try to do this (Polygon?) tend to apply it selectively, and I'm not sure it actually helps anyone. If you want good reviews, give the reviewers a good game in the first place. Post launch, only enthusiasts can be counted on to care about your game. The news and reviews cycle doesn't linger on anything except spectacular disasters.