The virus is showing no signs of slowing down last I heard, at least not in the US due to a certain someone who made a deal with Crowley, and even if it does go away, the movie and film industry will not recover, they'll lose all their knowledge and momentum after being inactive for so long.
And if they actually did plan to resume sometime, they'd be airing the episodes that were already finished. Season 4 of The Last Kingdom will come out on Netflix in 3 days. Where only the last two episodes of Supernatural haven't been filmed yet.
So I think, while they consider the possibility they MIGHT be able to release the last episodes, they just left off at one where you can headcanon the ending pretty quickly - saying Jack is pretty much destined to kill God, though leaving it unknown as to what role Sam and Dean play. (Maybe it'll kill Jack as well and he transfers his power to Sam and Dean so they can take God's place and turn the world into a paradise)
Besides, it looks like they're right on the edge of the final battle, what could possibly come between this episode and the final?
I swear, if Avengers: Endgame and a show whose final season, both of which I waited 7 years for, was last year, had been set for this year instead of last I'd be in an insane asylum right now. This is why they shouldn't make stuff go on for so long without "closure checkpoints", you never know what might stop it permanently.