It's perfectly fine to release a trailer for the next up-and-coming game in your established franchise. But instead of releasing the featured game a few months later, why not give another game you're developing a chance to steal the spotlight?
Annual franchises tend to be released just in time for the holiday season, which is obviously a marketing scheme to gain revenue from each unit sold. Developers should instead, use this opportunity to release a new IP to see how it fairs against competitors. An established franchise doesn't need help selling copies as much as a new one does.
And in the long run, that could help the company out financially.