>>24599418XY and ORAS weren't made with DLC in mind. If they wanted to add the ORAS shit to XY, they can't just take all the ORAS shit and plop them on the end, they would have to replace all the XY files with the ORAS ones. That would result in a patch that's over 1gb in size (which, considering XY were 1.8gb, is A FUCKING LOT), for a game that's now obsolete. There's literally no reason for them to do that whatsoever.
Picture related, can you tell which file contains all the models?