Your old Pokemon are not being deleted, you fucking idiots. Pokemon are not being retconned out of existence. You can still transfer things not in the Galarian Dex to Pokemon Home. No, you won't be able to use every single oldmon you want for your ingame team, but guess what? Almost every single gen put the transfer facility post E4.
Does this decision suck? Is Gamefreak being lazy and/or greedy? Yes, no one has denied that. Is it the end of the world, or the permanent end of half the dex? No. So chill the fuck out.