Larian said they were aiming to provide all the options of the PHB (race, class, background, hopefully-spells, etc), but probably not more than the PHB.
The XGtE and TCoE books are perfect material for new technical content in expansions, to go along with new story/quest content. So I would expect they'd rather keep this on the side of their desk, and not include it in the base game.
That being said, I'm hoping that some modders will implement this additional technical content. A lot of the new (sub)classes look pretty dope.
Hopefully they leave Tasha's out. The rules make race completely irrelevant.
You mean, the option to customise the Ability Score Increases and proficiencies of your character at character creation ? It's an
option. If you don't like it, nobody would force you to use it in your game. Why depriving other players of this options ?