do you seriously want that they sell you 3x of the same exact game? they already make 2 versions of the same game (for example alpha saphira and omega ruby) ok its fun to choose one and your friend chooses another, but having a third version would you buy any of the other 2? no one would get the other 2 with a third version...
when they made the core games, and at later time they release the same game with a revision and extra content, in the old days it was ok, but now when you can easily download an update it doesn't make much sense, specially with remakes, or does it?
if they remake the games then later release a more upgraded version of the remake, i wouldn't like that... pokemon makes little sense but that would be outrageous
anyway
you should get platinum then, its not a remake but its the next game from ruby..
if you preefer remake, then alpha saphira\omega ruby is really great.. and since you have a 3ds
never get x\y, while some folks liked it, i also liked it but it is a small game, after playing it, i have it on the closet...
the silver\gold remakes are great but they got a permanent small lag, after playing you get used to but its somehting that can be a bother for some folk
the firered and leafgreen remakes are ok, appearence is the same as ruby\emerald but at beggining it is almost exactly the originals, you can't get pokemon from other regions until after elite 4, and you go to a set of new small islands post game. if you have the ruby cartridge its a great addition to your collection