Quoted from jfh:
I honestly believe there is no longer a benefit to the manufacturers playing their cards so close to the vest. Let everyone know what the short term release plans are going to be (planned order, not exact release dates) so ops and collectors can plan for which titles they will get. It could provide a competitive advantage by keeping cash on the sidelines that might otherwise go toward a competitor’s pin.
I think the last year has shown us that you need to get the game out there ASAP. There will always be games coming out, and while some people might be saving their money, the rumor of what is next isn't a secret. The bigger missed opportunity is when you lose a lot of momentum on the excitement of your game due to a delayed release. These are impulse buys, not calculated investments (for the most part).
I don't think the reveal has to be at a show. If you can get pinball streamers and podcasters present during the week of your release, the hype will be there.