Konami has released cards in games that do not exist as cards in real life. Google it. There are entire list of cards that only exist in video games. Konami even created an "immortal" Type as in one of their games. They make these choices to keep balance or to get fans hype. You can doubt it if you wish but don't make it seem like they won't only because the card does not exist in the actual game
None of the recent video games, except for the Tag Force Series (Which was just done so there was a reason to buy it over the far superior World Championship Series), ever had any exclusive cards to them. Also why would they waste resources into making a card for Duel Links when they have thousands of already made cards that they can put in.
I already stated why and there is a list of cards that Konami put in games that were only in games. Just because you claim this only happened in Tag Force does not dislrove what I said. It actually confirms my point. Also Vegabond is from Tag Force series or rather based on the player character from there.
It does not matter if we ever get them or not. The point is, your logic is false. Konami has added cards in games thst were not released in card games and if they felt a desire to do it in Duel Links then it will happen. If this was only a Tag Force thing thwt makes it even more likeky because Duel Links is more infkuenced by Tag Force than other Konami made Yugioh Series.