I actually could see Pokémon giving out free DLC...cause they do it all the time. They even did it monthly for a whole year. Anytimr they give away a Pokémon through an event or code or whatever, that's technically DLC. They have contests and tournaments with DLC prizes. It's just not DLC that unlocks new areas or story quests. Although the game demos that unlock transfers and special Pokémon for us though could almost be considered free DLC with new story. Pokémon Bank is also almost DLC.
Now, I'm not saying this because I believe any of that rumor is true, just wanted to join on the DLC discussion. I think one day we can expect more expansive DLC for Pokémon, but I think they will keep a pretty good balance between paid and free DLC. I don't think Pokémon is ever going to bar certain Pokémon behind a paid DLC window. Sure, when games first come out there isn't typically a way to get all the Pokémon without using the bank, but it only takes a few people with some trading and breeding to start spreading those Pokémon around. Secondly, they tend to make the rest of the Pokémon available through the next game instalment in the franchise, and yes that is paid for, buts it's also a whole new other game (and if you don't buy it, trading is still a thing). The legendaries to remain pretty rare, but they also regularly have events and give aways for them. What I mean is, I don't think we're ever going to see Pokémon do a "Buy this DLC pack for $10.00 and gain access to Noir island where you can catch Weavile, Zorua, and Lucario! Unavailable anywhere else!!!"
I could see DLC paid stuff that unlocks a new side story...like a looker mission or Delta episode. It would probably gain you easier access to rare Pokémon, perhaps even wild versions of the games starters so you could get them in a different pokeball (and maybe hidden ability. And, the thing is, even with the people who didn't buy the DLC still have access to these Pokémon through global trade and wonder trade. That's the beauty of the social aspect of Pokémon, which is also a core values of the franchise). I could also see them doing paid DLC item stuff...like a clothing package with clothes that allows players to dress up like past Pokémon Characters or popular Pokémon themselves. I DON'T see them barring things like a battle frontier behind DLC. Maybe another restaurant or something, or a second nursery for hatching eggs.