>>40917885GameFreak has always been staunchly against DLC or Updates that simply weren't bug fixes; even recently, in his apology, Masuda mentioned that there were no plans in updating the games to include the National Dex.
Recently, he's backpedaled a bit and said that certain executive decisions would be made, pending the reception of SWSH - but my guess is that the definitive version coming out in a year or so will have the National Dex as a selling point, and was always intended to, without SWSH getting an update to make them compatible, just to let GameFreak squeeze as much money out of fans as possible.
You used to have get 2 versions to get all the Pokemon, or at least know someone with another copy, but now with online trading that's defunct. The dual releases have almost always been the same, with only minimal story differences and possibly a different villain team to fight, but GameFreak has toyed around with making the dual releases contain different content all the way back to Gen 5, with slightly different maps, but even now, the only major difference between the games are the 2 gyms exclusive to each version and the different dialogue based around your game's legendary. There isn't any reason for dual releases anymore without substantially changing each game's content, and GameFreak knows this, so instead of putting effort and giving people a reason to get both copies, they're going down a less scrupulous and trying to wring as much money from you as possible with the least amount of work.
