I think the sim will come much earlier than end of 2020, the way they have been bringing out information in the last weeks, episodes (next week we have the 3rd and in 2 weeks we have the 4th), the fact the game is already playable, makes me think we are not far away.
They have a very strong marketing dpmt and they are planning very carefuly when they are releasing what and I do not think they can keep up this level of info in the coming 9 months or so.
That they haven't shown the release date, I think it has more to do that it will depend on the Alpha 1 and 2 tests and may slightly vary depending on those.
My guess Q1 2020 ;-).