Possibly. Assuming this sale is an on-going monthly thing, and there's two catalogs per month like this month's, they can drag it out well until January-February without announcing anything. With Shiny Festa due out in October, they could also wait to announce a new game shortly after its release, though I'd imagine it would depend on how much DLC they plan to stretch out with those games. They'd be milking the crap out of that game with DLC first, I'd imagine.
Not any definite reasoning (considering the PS3 version of 2 was announced before the 360 catalogs were barely half-way finished), but it is some things to consider.