If it was that far away, they wouldn't announce it in 2018.
You can live under some false illusion it is coming earlier but he is right, they have been repeatedly hounded about it hence the early announcement. It's described as being in pre-production (so design/concept phase) and they have stated it will not arrive until after Starfield and both titles have been described as next-gen. We know from the Sony boss that the next consoles are due around 3 years from now. So it's not hard to deduce that the game is probably at best 4 years away. I would expect at least 4-5 years from design/concept which would put it at approx 2022/23.
I think 2021 is the most likely. No chance before 2020. As has been mentioned, they've not even started it apparently, and it's going to be released after Starfield which from the sounds of it is 2-3 years away
Starfield is more likely in 2021 I suspect given what I said above.
I hope so too. I've replayed Oblivion numerous times, Skyrim only once.
This could launch with the next generation of consoles.
Both Starfield and TES 6 were described as next-gen with Starfield coming first, I suspect Starfield is launch title with TES following 1-2 years after.