Originally posted by monochrome Canon, Nikon, Sony, Oly and Fuji can easily command all the space in all the print and blog review columns for weeks after a big show. Recent experience with the K-01 (I'm quite certain Pentax was unprepared for the negative tsunami) demonstrates PRI release dates might aim for the news holes between shows as well as using surprise (i.e. no pre-release rumors).
Just my supposition.
Shows are where all your trade customers and the press are, which these days includes drivers of fashion and influential bloggers. Miss that and you've missed a lot. Your suggestion would suit some but not all products, imho. Better to announce a product before a show so all can see and handle it, and hear your marketing team talking it up, than afterwards when hardly anyone will be able to scope it. Anyway, who knows. PRI may announce a new camera tomorrow; they may not make any announcements at all for six months.