The last time the majority of existing Pokèmon were removed from games and prevented from being brought over from previous generations was with the release of Ruby/Sapphire.

But this was remedied with the release of FrLg & Emerald, and between the 5 games all Pokèmon could be caught before the generation was out.

So do you think it's likely that the Pokèmon missing in SwSh will be added in later games (not patches), perhaps even in a remake?