There will be a large quantity of x670 motherboards available.
There will be a large quantity of x670 motherboards available.
No, the X670 motherboards won't be available for the Ryzen 5000 at least when it first launched.
It seems x670 won't be released anytime soon. For instance, ASUS recently introduced the Corshair Dark X570. X670 is expected to arrive around the same time as the B550, roughly six to five months later.
The plans for a fresh motherboard lineup aren't imminent. It seems likely this is just a theoretical announcement meant to signal future availability after supply stabilizes. This isn't unusual among top manufacturers, which makes it even more disappointing.
Not verified yet but looks plausible, no X670 available at the moment
I believe the upcoming chipset might be DDR5, possibly for Ryzen 6000 or 7000 models. I don't think AMD would create a new one since the X570 already performs well.