Remakes in this year aren't totally impossible. B2/W2 were announced 4 months before release. Interesting thing is that we started getting solid information only about 2 months before release. R/S remakes might be announced in August and start being promoted in September and October.
Maybe they are planning something like in 2004, when FR/LG got released outside Japan only 1 week before Emerald in Japan.
Btw, assuming World Tournament in B2/W2 is canon (because Koga is not present), and because Wallace is in Champions group, I think R/S remakes might even be in gen 5 timeline because in HG/SS Steven says he's the Champion and that he must go back to League, so he wasn't replaced by Wallace in gen 4 yet.