In case you were holding out: hope, dashed. Speaking to Inside Gamer, Pokemon boss Junichi Masuda re-confirmed that yes, there are no plans to add the National Pokedex into Sword and Shield.
Although there were some "maybes" thrown out since the news came back in June at E3, Game Freak is now sticking to their guns and eliminating the prospect altogether. Masuda states: "We now have no plans to make the Pokemon that are missing in the Galar Pokedex in-game available. That is an approach that we want to continue with Pokemon games in the future. Of course, up to now it has not been possible to encounter every Pokemon in every game, so people had to transfer it from old games via Pokemon Bank to the new game, for example."
Masuda again explains that it's a question of "manpower," on top of all the new features found in Sword and Shield, and hopes that players will instead accept the concession of the upcoming Pokemon Home app. He notes: "We encourage people to use Pokemon Home to collect their Pokemon from old games there. From there, they might be able to take it to other games in the future. So take good care of your old Pokemon, because you might be able to go out with them again in the future."
This whole situation has been fascinating to watch unfold. After 21 years (in the US) we've finally reached the point where you can't "collect them all," which I understand is disappointing. But I can recall discussing the bloat with other Pokemon players even as early as Generation 3 (Ruby and Sapphire), where a lot of people felt the sheer number of creatures was becoming unwieldy. I've actually caught them all since the first generation on, and I feel like now is an acceptable time to retire from that endeavor.
That said we'll see how compelling the endgame is for Sword & Shield soon enough, because without the National 'Dex component it could have a very short life cycle of relevancy.
Inside Gamer [Pokemon Sword & Shield]